Radiation Shielding efficiency of lead-tungsten-boron glasses with Sb, Al, and Bi against gamma, neutron and charge particles

We report on newly developed nuclear shielding glass system based on lead-tungsten-boron (PWB) for radiation applications against photon, neutron and charge particles. This newly developed system contains also different additions, in low concentrations, such as Sb, Al and Bi. The gamma/photon shielding performance was tested by using FLUKA Monte Carlo. Moreover, the shielding efficiency of the present system is examined against charged particles (light and heavy ones) and neutrons. The highest gamma/photons attenuation is observed in the lowest incident energy and this is at the region of the photoelectric absorption. We also observe that the values of effective atomic number (Zeff) show a peak at 100 keV incident energy. The reduction of these values is higher for photon energy range 0.1-1 MeV than below 80 keV energies. The lowest half value layer (d1/2), reflecting the best shielding efficiency, is recorded for the PWB-Bi system. The PWB-Bi system demonstrates promising performance better than many of commercial and standard systems and heavy concretes.

Radiation attenuation of boro-tellurite glasses for efficient shielding applications

The borotellurite glasses whose chemical structure is (29.5-0.4x)CaO + 10CaF2 + (60-0.6x)B2O3 + xTeO2+ 0.5Yb2O3 (where x=10, 16, 22, 31, and 54 % mole. represent TCCBY1-TCCBY5, respectively) are Pb-free, thermally stable, and transparent glasses with attractive optical features for technological applications. The gamma-photons, electrons, protons, neutrons, carbon ions, fast neutrons, and fast neutron interaction parameters of these glasses are presented in this study to better understand the role of TeO2 in influencing their radiation shielding properties and radiation protection applications. The photon mass attenuation coefficient was evaluated by XCOM computation and simulation using the FLUKA code. The FLUKA code was also used to evaluate the mass stopping powers of the charged radiations, while neutrons' cross sections were evaluated using standard expressions. For 0.015 MeV-15 MeV photons, the mass attenuation coefficients of the glasses fell from 17.9499 to 0.0246 cm2/g for TCCBY1, 20.5628 to 0.0263 cm2/g for TCCBY2, 23.2756 to 0.079 cm2/g for TCCBY3, 26.7487 to 0.0298 cm2/g for TCCBY4, and 33.3591 to 0.0335 cm2/g for TCCBY5. The photon half-value layer at 15 keV is reduced by about 19.57%, 32.68%, 48.84%, and 63.89% when the TeO2 content increases from 10 mol to 16, 22, 31, and 54 mol, respectively. TeO2 was found to suppress photon buildup in the glasses. The mass stopping powers of charged radiation increased as glass density decreased. The addition of TeO2 into the glass structure increased the ability of the TCCBY glass to absorb fast neutrons by up to 54 % mole. The gamma radiation and fast neutron moderating ability of TCCBY5 glass compared to common shields and other materials is exceptional. The glass is recommended for the design of Pb-free, transparent, and efficient radiation protection structures.

Cobalt Ferrite Surface-Modified Carbon Nanotube Fibers as an Efficient and Flexible Electrode for Overall Electrochemical Water Splitting Reactions

One of the most practical and environmentally friendly ways to deal with the energy crises and global warming is to produce hydrogen as clean fuel by splitting water. The central obstacle for electrochemical water splitting is the use of expensive metal-based catalysts. For electrocatalytic hydrogen production, it is essential to fabricate an efficient catalyst for the counterpart oxygen evolution reaction (OER), which is a four-electron-transfer sluggish process. Here in this study, we have successfully fabricated cobalt-based ferrite nanoparticles over the surface of carbon nanotube fiber (CNTF) that was utilized as flexible anode materials for the OER and overall electrochemical water splitting reactions. Scanning electron microscopy images with elemental mapping showed the growth of nanoparticles over CNTF, while electrochemical characterization exhibited excellent electrocatalytic performance. Linear sweep voltammetry revealed the reduced overpotential value (260 mV@η10mAcm-2) with a small Tafel slope of 149 mV dec-1. Boosted electrochemical double layer capacitance (0.87 mF cm-2) for the modified electrode also reflects the higher surface area as compared to pristine CNTF (Cdl = 0.022 mF cm-2). Charge transfer resistance for the surface-modified CNTF showed the lower diameter in the Nyquist plot and was consequently associated with the better Faradaic process at the electrode/electrolyte interface. Overall, the as-fabricated electrode could be a promising alternative for the efficient electrochemical water splitting reaction as compared to expensive metal-based electrocatalysts.

Ba2-xHoxSr2-yNiyFe12O22 and its composite with MXene: synthesis, characterization and enhanced visible light mediated photocatalytic activity for colored dye and pesticide

The rapid recombination of charges of photogenerated electrons and holes severely limits single semiconductor photocatalytic applications. In this study, a simple and facile sol-gel approach was used to synthesize Ba2-xHoxSr2-yNiyFe12O22 (x = 0, 0.1 and y = 0, 0.5). The composite of holmium-nickel doped barium-strontium ferrite with MXene (Ba1.9Ho0.1Sr1.5Ni0.5Fe12O22@MXene) was synthesized by ultrasonication method. These synthesized samples were subsequently used to photodegrade rhodamine B (RhB) and pendimethalin under visible light illumination. The results of the experiments demonstrated that MXene, as a cocatalyst, considerably reduces the rate of recombination of charges and broadens absorption of visible light by providing increased surface functional groups to improve the photocatalytic activity of synthesized samples. MXene is thermally stable, have high electrical conductivity, have adjustable bandgap, and hydrophilic in nature. The optimized Ba1.9Ho0.1Sr1.5Ni0.5Fe12O22@MXene composite demonstrated an excellent photocatalytic rate by degrading 78.88% RhB and 75.59% pendimethalin in 140 minutes. Moreover, the scavenging experiment revealed that photogenerated electrons and holes were the primary active species involved in RhB and pendimethalin photodegradation, respectively. Ba1.9Ho0.1Sr1.5Ni0.5Fe12O22@MXene showed increased photocatalytic behavior because it has increased surface area which decreases rate of recombination of electron and hole pair, hence photocatalytic activity increases. It is observed that Ba1.9Ho0.1Sr1.5Ni0.5Fe12O22@MXene has potential application in photocatalytic degradation of harmful pollutants.

Neutron attenuation features and elastic properties of silicate glasses containing Ta2O5, and Li2O

In this investigation, the elastic properties and neutrons attenuation factors for some optical glasses containing Ta₂O₅, SiO₂, and Li₂O were reported. The present glasses were also consisted of ZrO₂ and Nb₂O₅ in very small concentrations. The glasses are chemically defined as 26.47Li₂O-5.88ZrO₂-(20-x)Ta₂O₅-xNb₂O₅-47.06SiO2, where, x takes the values: 0, 2.94, 5.88, and 11.77 mol%. The elastic properties of these glassy specimens were determined by employing Makishima-Mackenzie's theory (M.M.T). By using the same method, moreover, the micro-hardness and Poisson's ratio were assessed. Cross sections for slow, moderated, and fissile neutrons were computed through standard expressions and models. In addition, the influence of the partial replacement of Ta₂O₅ by Nb₂O₅ on the parameters were also analysed. The glass with the lowest Nb₂O₅ content presented the highest cross sections for fast, moderated, and slow neutrons. The neutron-absorption ability of included glasses declined as glass density declined and Nb₂O₅ molar concentration increased in the glasses. Therefore, the sample with the highest Ta₂O₅ content is recommended for neutron absorption applications.

Heavy metals biosensor based on defective one-dimensional phononic crystals

In recent years, the detection of water pollution with low levels of heavy metals has attracted the great attention of many researchers as a result of the imminent danger of this type of pollution to all mankind. Meanwhile, we introduce a theoretical approach based on the one-dimensional phononic crystals (1D-PnCs) with a central defect layer as a novel platform for the highly sensitive detection of heavy metal pollution in freshwater. Therefore, the creation of a resonant peak in the transmittance spectrum related to this defect layer is highly conceivable. In this regard, the detection of cadmium chloride (CdCl₂) as a dangerous, toxic, and extremely hazardous heavy metal could be investigated based on the small displacement in the position of this resonant peak with the changes in the CdCl₂ concentration. Notably, any change in CdCl₂ concentration has a direct impact on its acoustic properties. The theoretical framework of our research study is essentially based on the 2 × 2 transfer matrix method and the acoustic properties of the constituent materials as well. The optimization of all sensor parameters represents the mainstay of this study to get the best sensor performance. In this regard, the proposed sensor has a remarkably high sensitivity (S = 1904.25 Hz/ppm) over a concentration range of 0 - 10000 ppm. In addition, the sensor has a high quality factor (QF), and figure of merit of 1771.318, and 73529410^-5 (ppm^-1), respectively. Finally, we believe this sensor could be a key component of a feasible platform for detecting low concentrations of different heavy metal ions in freshwater.

Radiation shielding competence of chalcogenide alloys with high Te content

In this research paper, we report on the radiation shielding ability of five newly developed chalcogenide alloys described by the chemical compositions of Ge₂₀Sb₆Te₇₂Bi₂ (GTSB1), Ge₂₀Sb₆Te₇₀Bi₄ (GTSB2), Ge₂₀Sb₆Te₆₈Bi₆ (GTSB3), Ge₂₀Sb₆Te₆₆Bi₈ (GTSB4), and Ge₂₀Sb₆Te₆₄Bi₁₀ (GTSB5). The simulation (Monte Carlo) technique is systematically utilized to understand the problem of radiation propagation through the chalcogenide alloys. The maximum deviation between the theoretical values and simulations outcomes for each alloy sample corresponds to circa 0.525, 0.517, 0.875, 0.619, and 0.574% for GTSB1, GTSB2, GTSB3, GTSB4, and GTSB5, respectively. The obtained results indicate that the rapid decline in the value of the attenuation coefficients is mainly due to the main photon interaction process with the alloys for E≤500 keV. Additionally, the charged particle and neutron transmission properties are assessed for the involved chalcogenide alloys. Comparing the MFP and HVL with those of the conventional shielding glasses and concretes, the present alloys are good photon absorbers and they could be used to replace some conventional shields in radiation protection applications.

Radiation shielding ability and optical features of La2O3+TiO2+Nb2O5+WO3+X2O3 (X=B, Ga, and In) glass system containing high-entropy oxides

Three high entropy materials (La₂O₃+TiO₂+Nb₂O₅+WO₃+X₂O₃ coded as LTNWM1, LTNWM2, and LTNWM3 for X = B, Ga, and In) produced by aerodynamic containerless processing were evaluated for optical attributes, and their gamma-radiation absorption abilities were investigated in this report. Optical related parameters such as the molar refractivity ( R m ), optical transmission ( T ), molar polarizability ( α m ), metallization criterion ( M ), reflection loss ( R L ), static ( ε s t a t i c ), and optical ( ε o p t i c a l ) dielectric constants were estimated through standard expressions, while photon attenuation parameters were estimated from data from photon transmission simulations in FLUKA code and XCOM software. The attenuation parameters were calculated for a wide energy photon spectrum (15 keV-15 MeV). LTNWM1, LTNWM2, and LTNWM3 had R m values of 18.94 cm³/mol, 21.45 cm³/mol, and 26.09 cm³/mol respectively. The α m has a value of 7.52 × 10^-24 cm³ for LTNWM1, 8.51 × 10^-24 cm³ for LTNWM2, and 10.35 × 10^-24 cm³ for LTNWM3. The photon shielding parameters evaluated by FLUKA and XCOM are compatible. The mass attenuation coefficient for the glasses was between 0.0338 and 52.8261 cm²/g, 0.0336-58.0237 cm²/g, and 0.0344-52.1560 cm²/g for LTNWM1, LTNWM2 and LTNWM3, respectively. The effective atomic number at 1.5 MeV was 18.718, 20.857, and 22.440 for LTNWM1, LTNWM2, and LTNWM3, respectively. The shielding parameters of the HMOs compared to traditional gamma radiation absorbers are exceptional and highlight the potential of using them as optically transparent gamma-shields.

In-silico Investigations of quinine and quinidine as potential Inhibitors of AKR1B1 and AKR1B10: Functional and structural characterization

The aberrant expression of aldo keto reductases (AKR1B1 & AKR1B10) has been extensively studied in different types of cancer especially the colon cancer but a very few studies have yet been reported regarding the discovery of inhibitors for the treatment of colon cancer by targeting these isozymes. Therefore, there is a need of selective inhibitors of both targets for the eradication of colon cancer. Currently, the study is focused on the exploration of two quinolone compounds i.e., (S)-(6-Methoxyquinolin-4-yl)[(1S,2R,4S,5R)-5-vinylquinuclidin-2-yl]methanol (Quinidine) and (R)-(6-Methoxyquinolin-4-yl)[(1S,2S,4S,5R)-5-vinylquinuclidin-2-yl]methanol (Quinine) as the potential inhibitors of AKR1B1 and AKR1B10 via detailed in-silico approach. The structural properties including vibrational frequencies, dipole moment, polarizability and the optimization energies were estimated using density functional theory (DFT) calculations; where both compounds were found chemically reactive. After that, the optimized structures were used for the molecular docking studies and here quinidine was found more selective towards AKR1B1 and quinine exhibited maximum inhibition of AKR1B10. The results of molecular docking studies were validated by molecular dynamics simulations which provided the deep insight of stability of protein ligand complex. At the end, the ADMET properties were determined to demonstrate the druglikeness properties of both selected compounds. These findings suggested further exploration of both compounds at molecular level using different in-vivo and in-vitro approaches that will lead to the designing of potential inhibitor of AKR1B1/AKR1B10 for curing colon cancer and related malignancies.

Identification of NEK7 inhibitors: structure based virtual screening, molecular docking, density functional theory calculations and molecular dynamics simulations

NEK7 is a NIMA related-protein kinase that plays a crucial role in spindle assembly and cell division. Dysregulation of NEK7 protein leads to development and progression of different types of malignancies including colon and breast cancers. Therefore, NEK7 could be considered as an attractive target for anti-cancer drug discovery. However, few efforts have been made for the development of selective inhibitors of NIMA-related kinase but still no FDA approved drug is known to selectively inhibit the NEK7 protein. Dacomitinib and Neratinib are two Enamide derivatives that were approved for treatment against non-small cell lung cancer and breast cancer respectively. Drug repurposing is a time and cost-efficient method for re-evaluating the activities of previously authorized medications. Thus, the present research involves the repurposing of two FDA-approved medications via comprehensive in silico approach including Density functional theory (DFTs) studies which were conducted to determine the electronic properties of the Dacomitinib and Neratinib. Afterward, binding orientation of selected drugs inside NEK7 activation loop was evaluated through molecular docking approach. Selected drugs exhibited potential molecular interactions engaging important amino acid residues of active site. The docking score of Dacomitinib and Neratinib was -30.77 and -26.78 kJ/mol, respectively. The top ranked pose obtained from molecular docking was subjected to Molecular Dynamics (MD) Simulations for investigating the stability of protein-ligand complex. The RMSD pattern revealed the stability of protein-ligand complex throughout simulated trajectory. In conclusion, both drugs displayed inhibitory efficacy against NEK7 protein and provide a prospective therapy option for malignant malignancies linked with NEK7. Communicated by Ramaswamy H. Sarma.

Sonophotocatalytic Dye Degradation Using rGO-BiVO4 Composites

Reduced graphene oxide (rGO)/bismuth vanadate BiVO₄ composites are fabricated with varied rGO amounts (0, 1, 2, and 3 wt%) through the synergetic effects of ultrasonication, photoinduced reduction, and hydrothermal methods, and the materials are tested as tools for sonophotocatalytic methylene blue (MB) dye degradation. The effect of rGO content on the sonophotocatalytic dye degradation capabilities of the composites are explored. Characterization of the proposed materials is done through transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transformation infrared spectroscopy as well as scanning electron microscopy. The coexistence of BiVO₄ and rGO is confirmed using Raman spectroscopy and XRD. TEM confirms the existence of interfaces between rGO and BiVO₄ and XPS affirms the existence of varied elemental oxidation states. In order to investigate the charge carriers transportation, time-dependent photocurrent responses of BiVO₄ and 2 wt%- rGO/BiVO₄ are done under visible light irradiation. The sonophotocatalytic MB dye degradation in an aqueous medium displays promising enhancement with rGO doping in rGO/BiVO₄ composite. The 2 wt%- rGO/BiVO₄ sample exhibits ≈52% MB dye degradation efficiency as compared to pure BiVO4 (≈25%) in 180 min of the sonophotocatalysis experiment. Phytotoxicity analysis through germination index is done using vigna radiata seeds.

Simple, efficient and accurate method toward the monitoring of ethyl butanoate traces

We introduce in this research a simple, accurate, safe, and efficient design for the detection of ethyl butanoate that be present in the dry exhaled breath. In particular, the presence of ethyl butanoate in the dry exhaled breath could be utilized as a platform for the diagnosing of COVID 19. The main idea of this theoretical investigation is based on the inclusion of a cavity layer between a thin layer of Au and the well-known one-dimension photonic crystals. Accordingly, the cavity layer is filled with dry exhaled breath. The numerical results are investigated in the vicinity of the Drude model and transfer matrix method. The investigated results show the appearance of Tamm plasmon resonance in the reflectance spectrum of our design through the IR region. Such resonant mode provides very high sensitivity with the change in the concentration of ethyl butanoate. We have examined the performance of the proposed sensor by calculating its sensitivity, detection limit, detection accuracy, quality factor and figure of merit. The designed sensor could receive sensitivity of 0.3 nm/ppm or 260,486 nm/RIU, resolution of 7 ppm and quality factor of 969.

Electronic and optical properties of bulk and surface of CsPbBr3 inorganic halide perovskite a first principles DFT 1/2 approach

This work aims to test the effectiveness of newly developed DFT-1/2 functional in calculating the electronic and optical properties of inorganic lead halide perovskites CsPbBr3. Herein, from DFT-1/2 we have obtained the direct band gap of 2.36 eV and 3.82 eV for orthorhombic bulk and 001-surface, respectively. The calculated energy band gap is in qualitative agreement with the experimental findings. The bandgap of ultra-thin film of CsPbBr3 is found to be 3.82 eV, which is more than the expected range 1.23-3.10 eV. However, we have found that the bandgap can be reduced by increasing the surface thickness. Thus, the system under investigation looks promising for optoelectronic and photocatalysis applications, due to the bandgap matching and high optical absorption in UV-Vis (Ultra violet and visible spectrum) range of electro-magnetic(em) radiation.

Comparison of different adsorption pairs based on zeotropic and azeotropic mixture refrigerants for solar adsorption ice maker

One of the important ways to the efficiently use of low-grade thermal energy is the adsorption refrigeration technology. However, it has some drawbacks such as low specific cooling power and coefficient of performance, especially under using the conventional adsorption pairs. Therefore, new adsorption pairs are tested in solar adsorption ice-maker and compared with other conventional pairs data from open literature to find the tendency of improving the solar adsorption ice-maker performance. The experimental test rig has been built in Upper Egypt in Qena City. Four different new adsorption pairs of granular activated carbon/R-410A, granular activated carbon/R-511A, Maxsorb III/R-410A, and Maxsorb III/R-511A are used. It is demonstrated that Maxsorb III/R-511A pair based solar adsorption ice-maker produced the highest values for specific cooling power, coefficient of performance, and ice production per 1 kg of adsorbent of approximately 226.7 W/kg_ads, 0.197, and 1.96 kg/kg_ads, respectively. While granular activated carbon/R-410A based solar adsorption ice-maker produced the lowest values of ice production per 1 kg of adsorbent and coefficient of performance of 1.38 kg/kg_ads and 0.104, respectively. Moreover, it can be concluded that the tested pairs are feasible to be used in solar adsorption ice-maker systems, especially in such hot climate of Upper Egypt for food and vaccine preservation and storage.

SOIL-SOYBEAN TRANSFER FACTOR OF NATURAL RADIONUCLIDES IN DIFFERENT SOIL TEXTURES AND THE ASSESSMENT OF COMMITTED EFFECTIVE DOSE

From three different soil textures (clay, silt and sand), 36 soil and soybeans samples were accumulated from the agricultural area of EL-Mynia governorate in Upper Egypt, between (27°36'19.44″N; 30°30'14.14″ E) and (28°48'28.45″ N; 31°00'32.27″ E). Soil textures were prepared by particle size distribution through a pipette method. Its radioactivity measurements were performed with a NaI (Tl) and 3 × 3 inch crystal. The transfer factor (TF) of natural radionuclides from soil to soybeans was calculated. The value of the TF for 226Ra in clay soil ranges from 0.27 ± 0.03 to 0.42 ± 0.05, in sandy soil it ranges from 0.21 ± 0.02 to 0.57 ± 0.07 and in silt soil it ranges from 0.25 ± 0.03 to 0.53 ± 0.06. The TF for 232Th in clay soil ranges from 0.22 ± 0.03 to 0.90 ± 0.12, in sandy soil it ranges from 0.21 ± 0.03 to 1.00 ± 0.13, while in silt soil it ranges from 0.25 ± 0.03 to 0.88 ± 0.12. The TF for 40K in clay soil ranges from 0.95 ± 0.13 to 2.05 ± 0.29, in sandy soil it ranges from 1.21 ± 0.17 to 2.52 ± 0.35 and in silt soil it ranges and from 1.01 ± 0.14 to 1.46 ± 0.26.The results show that the committed effective dose from soybean consumption is between 54.5 and 103.4 μSv y-1 assuming consumption of 20 kg y-1.