Impact of ZnO Modifier Concentration on TeO2 Glass Matrix for Optical and Gamma-Ray Shielding Capabilities.

This study carried out a comparison of the optical and gamma ray shielding features of TeO2 with and without ZnO modifier concentration. Incorporating ZnO into the TeO2 network reduces the indirect band gap from 3.515-3.481 eV. When ZnO is added, refractive indices, dielectric constants, and optical dielectric constants rise from 2.271-2.278, 5.156-5.191, and 4.156-4.191 accordingly. The transmission coefficient and reflection loss are in direct opposition to each other. With increasing ZnO concentration in the selected glasses, the values of molar refractivity and molar polarizability decrease from 18.767-15.018 cm3/mol and from 7.444 × 10-24-5.957 × 10-24 cm3, respectively, while the electronic polarizability rises from 8.244 × 1024-8.273 × 1024, correspondingly. As expected by the metallization values, the glass systems are non-metallic. The linear attenuation coefficients (LAC) of the studied glass samples ensue through enhancing the photon energy range 0.0395-0.3443 MeV. There is a very slow decrease in the LAC from an energy of 0.1218-0.3443 MeV, yet there is a sharp decrease from an energy of 0.0401-0.0459 MeV. According to the obtained values of numerous shielding parameters such as LAC, MAC, HVL, MFP, and Zeff sample, Zn30 has shown the best radiation shielding ability comprising other studied samples.

Design and Gamma-Ray Attenuation Features of New Concrete Materials for Low- and Moderate-Photons Energy Protection Applications.

We aimed, in this investigation, to prepare novel concretes which can be used in gamma-ray shielding applications. The experimental approach was performed using a NaI (Tl) detector to measure the concrete's shielding features for different energies, ranging from 0.081 MeV to 1.408 MeV. The density of the fabricated concretes decreased with increasing W/C ratio, where the density decreased by 2.680 g/cm3, 2.614 g/cm3, and 2.564 g/cm3 for concretes A, B, and C, respectively, with increases in the W/C ratio of 0.4, 0.6, and 0.8, respectively. When the energy was elevated between 0.08 MeV and 1.408 MeV, the highest values were attained for concrete A, with values ranging between 0.451 cm-1 and 0.179 cm-1. The lowest half-value layer (Δ0.5) values were achieved for concrete C, where the Δ0.5 values varied between 1.53 cm and 3.86 cm between 0.08 MeV and 1.408 MeV. The highest Δ0.5 values were achieved for concrete A, where the Δ0.5 varied between 1.77 cm and 4.67 cm between 0.08 MeV and 1.408 MeV. According to this investigation, concrete A has the highest promise in radiation shielding purposes because it has the most desirable properties of the concretes studied.

A Study of Ta2O5 Nanopillars with Ni Tips Prepared by Porous Anodic Alumina Through-Mask Anodization.

The paper discusses the formation of Ta2O5 pillars with Ni tips during thin porous anodic alumina through-mask anodization on Si/SiO2 substrates. The tantalum nanopillars were formed through porous masks in electrolytes of phosphoric and oxalic acid. The Ni tips on the Ta2O5 pillars were formed via vacuum evaporation through the porous mask. The morphology, structure, and magnetic properties at 4.2 and 300 K of the Ta2O5 nanopillars with Ni tips have been studied using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. The main mechanism of the formation of the Ta2O5 pillars during through-mask anodization was revealed. The superparamagnetic behavior of the magnetic hysteresis loop of the Ta2O5 nanopillars with Ni tips was observed. Such nanostructures can be used to develop novel functional nanomaterials for magnetic, electronic, biomedical, and optical nano-scale devices.

Rapid and Sensitive Detection of Severe Acute Respiratory Syndrome Coronavirus 2 in Label-Free Manner Using Micromechanical Sensors.

Coronavirus (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has been identified as a deadly pandemic. The genomic analysis of SARS-CoV-2 is performed using a reverse transcription-polymerase chain reaction (RT-PCR) technique for identifying viral ribonucleic acid (RNA) in infected patients. However, the RT-PCR diagnostic technique is manually laborious and expensive; therefore, it is not readily accessible in every laboratory. Methodological simplification is crucial to combat the ongoing pandemic by introducing quick, efficient, and affordable diagnostic methods. Here, we report how microcantilever sensors offer promising opportunities for rapid COVID-19 detection. Our first attempt was to capture the single-stranded complementary DNA of SARS-CoV-2 through DNA hybridization. Therefore, the microcantilever surface was immobilized with an oligonucleotide probe and detected using complementary target DNA hybridization by a shift in microcantilever resonance frequency. Our results show that microcantilever sensors can discriminate between complementary and noncomplementary target DNA on a micro to nanoscale. Additionally, the microcantilever sensors' aptitude toward partial complementary DNA determines their potential to identify new variants of coronavirus. Therefore, microcantilever sensing could be a vital tool in the effort to extinguish the spreading COVID-19 pandemic.

Uptake prediction of nine heavy metals by Eichhornia crassipes grown in irrigation canals: A biomonitoring approach.

The principal objective of this study is to generate mathematical regression equations that facilitate the estimation of the extent to which Eichhornia crassipes (C. Mart.) Solms, water hyacinth, absorbs heavy metals (HMs) into four plant organs (laminae, petioles, roots, and stolons). This study considers the absorption of nine HMs (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn), and the E. crassipes evaluated in this study were located in three irrigation canals in the North Nile Delta in Egypt, with sampling being conducted in both monospecific and homogenous E. crassipes. Samples of both E. crassipes and water were collected on a monthly basis during one growing season. Analysis of the water samples showed that the HM concentrations ranged from 1.1 µg/l for Cd to 2079.8 µg/l for Fe. All HMs were more concentrated in the E. crassipes roots than in any other organ. Typically, there was a significant correlation between the HM levels in the water and the HM levels in the E. crassipes organs. E. crassipes was documented by a bioconcentration factor > 1.0 for all HMs. The translocation factor in this study was <1.0 for all HMs. The t-values that referred to the discrepancies between the measured and predicted values of the HMs in the four E. crassipes organs were not significant. This finding can be considered to be an indication of the goodness of fit with respect to the ability of the equations to forecast HM uptake. Therefore, the developed equations will benefit the prediction of HM uptake by E. crassipes grown in irrigation canals in the Nile Delta. The efficacy of E. crassipes as a metric for gauging the aggregate impact of environmental pollution in water sources and its potential application in biomonitoring are confirmed in this study.

Gamma Attenuation Coefficients of Nano Cadmium Oxide/High density Polyethylene Composites.

In the present work, high density polyethylene (HDPE) matrix mixed with micro-sized and nano-sized Cadmium oxide (CdO) particles of different concentrations were prepared by compression molding technique. The aim of the study is to investigate the effect of particle size and weight percentage of CdO particles on the gamma radiation shielding ability of CdO/HDPE composites. The mass attenuation coefficients of pure HDPE, micro-CdO/HDPE and nano-CdO/HDPE composites were evaluated at photon energies ranging from 59.53 keV to 1408.01 keV using standard radioactive point sources [241Am, 133Ba, 137Cs, 60Co and 152Eu]. Adding micro and nano CdO particles to the HDPE matrix clearly increases the mass attenuation coefficients of the composites and the improvement is more significant at low γ-ray energies. The effect of particle size of CdO filler has an important role on the shielding ability of the composite. The experimental results reveal that, the composites filled with nano-CdO have better γ-radiation shielding ability compared to that filled with micro-CdO at the same weight fraction. A relative increase rate of about 16% is obtained with nano-CdO content of 40 wt% at 59.53 keV, which attributed to the higher probability of interaction between γ-rays and nanoparticles. From this study, it can be concluded that nano-CdO has a good performance shielding characteristic than micro-CdO in HDPE based radiation shielding material.

Evaluation of the Activity of Gamma-Emitting Natural Radionuclides in Seafood and Estimation of the Annual Effective Dose for Different Age Groups in KSA.

Twenty-six brands of canned tuna and sardines imported from several countries in Southeast Asia to consume in the KSA. All samples were prepared and analyzed by using a High Pure Germanium Detector of 40% efficiency. Natural radionuclides 40K, 238U (226Ra) and 232Th(228Ra) series were observed with a varying range in all analyzed samples. The values found to be 192.3 ± 14.6, 1.5 ± 0.8 and 1.0 ± 0.6 Bq kg-1 for canned tuna and 219.8 ± 15.8, 0.37 ± 0.3 and 1.2 ± 0.3 Bq kg-1 for canned sardines, respectively. Cesium-137 was not detected at any sample. The comparison between the average activity concentrations of 40K, 238U(226Ra) and 232Th(228Ra) in both canned tuna and sardines was performed and discussed. The dose assessment due to consume/ingestion of seafood was calculated and observed that the calculated committed effective dose is within the global internal dose (290 µSv/y).