ABSTRACT
Aiming to extend the scope of utilizing glass in radiation shielding, this work investigates the radiation interaction response of a borate-based glass system. Four borate-glass samples of different substituting concentrations of calcium oxide ( 70 - x )B2O3: 10 Na2O : 5 Al2O3 : 15 BaO: x CaO were prepared. To assess the shielding performance of the prepared glass samples, a high-purity germanium detector and different radioactive sources (different energies) were used. Via the narrow beam method, the linear attenuation coefficients (LACs) were experimentally measured. So, the transmission factor (TF), the half-value layer (HVL), the tenth value layer (TVL), the mean free path (MFP), and the radiation protection efficiency (RPE) were calculated for all prepared samples. It was observed that the increase of the concentration of calcium oxide in the proposed borate-based glass samples leads to improve their performance in shielding against radiation. At low energy, the RPE of the samples is almost 100%. However, it was observed that as energy of the radiation source increases, the shielding performance of the samples will decrease. High energy dependence was found when calculating TF, HVL, TVL, and MFP. They were increased with the increase of the energy of the incident photons. At 0.662 MeV, the TF values are equal to 79.26, 79.00, 79.72, and 78.43% for BNABC-1, BNABC-2, BNABC-3, and BNABC-4 in the same oder, respectively. The application of the proposed composition of borate-based glass as a transparent shield against low-energy ionizing radiation was highlighted.
ABSTRACT
BACKGROUND: The design and fabrication of hemocompatible and low-toxicity formulations remains a challenging task. Hydrogels are of considerable importance for biomedical applications since they are highly compatible with living tissue, both in vivo and in vitro. OBJECTIVE: The present study aimed to develop and evaluate the characterizations and in vitro hemocompatibility of a hydrogel using polyvinyl alcohol and gelatin with different concentrations. METHODS: The gelling process was realized by cross-linking the polyvinyl alcohol and gelatin. The morphological and structural examinations of the synthetic hydrogels were done by scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The swelling behavior of the prepared hydrogels in water was evaluated. Prothrombin time, activated partial thromboplastin time, and thrombin time were measured, and a hemolysis test was done to evaluate the hemocompatibility of prepared hydrogels. RESULTS: The increase of the gelatin concentration in polyvinyl gelatin hydrogel increases the porosity and enhances the absorptivity of the prepared hydrogel. The measured hematological parameters indicated enhancement of hemocompatibility as the gelatin concentration was increased in the prepared hydrogel. CONCLUSIONS: The results obtained from this study confirm that gelatin was able to improve the properties of the polyvinyl alcohol-gelatin hydrogel and enhance the hemocompatibility. Thus, the prepared hydrogel could be used in a variety of biomedical applications.
Subject(s)
Gelatin , Polyvinyl Alcohol , Hydrogels , Porosity , WaterABSTRACT
Fourier transform infrared (FTIR) spectrum dielectric constant, ε', loss tangent, tan(δ), electric modulus, M*, and ac conductivity, σ(ac), of pure polyvinyl alcohol (PVA) as well as La-, Gd-, and Er-PVA doped samples have been carried out. The dielectric properties have been studied in the temperature and frequency ranges; 300-450 K and 1 kHz-4 MHz, respectively. FTIR measurements reveal that La(3+), Gd(3+), and Er(3+) ions form complex configuration within PVA structure. Two relaxation processes, namely, ρ and α were observed in pure PVA sample. The first process is due to the interfacial or Maxwell-Wagner-Sillers polarization. The second one is related to the micro-Brownian motion of the main chains. For doped PVA samples, α-relaxation process splits into α(a) and α(c). This splitting is due to the segmental motion in the amorphous (α(a)) and crystalline (α(c)) phases of PVA matrix. Electric modulus analysis was discussed to understand the mechanism of the electrical transport process. The behavior of ac conductivity for all PVA samples indicates that the conduction mechanism is correlated barrier hopping.
