Thorium-230 has many research applications, but there is not a commercial source of this isotope. However, since 230Th is part of the 238U decay chain, it can be separated from naturally occurring uranium. In this work, a novel procedure was developed to separate thorium from uranium ore, consisting of leaching, liquid–liquid extraction, precipitations and ion exchange chromatography. The final product was 91.32?±?0.77 mg of thorium with a purity of 99.5?±?1.2 wt%. Of that, 7.65?±?0.10 mg was 230Th and the remainder 232Th. The total yield of 230Th was 71.1?±?5.4%. Ways to improve the yield by further processing the back-extraction solution are suggested.
相似文献The activity concentrations of 226Ra, 228Ra and 222Rn were measured in 87 groundwater samples to estimate the activity concentrations of these radionuclides and health impact due to intake of these radionuclides in groundwater of Jordan. The mean activity concentrations of 226Ra, 228Ra and 222Rn in groundwater were found to be 0.293?±?0.005 Bq L?1, 0.508?±?0.009 Bq L?1 and 58.829?±?8.824 Bq L?1, respectively. They give a mean annual effective dose of 0.481 mSv with mean lifetime risk of 24.599?×?10?4, exceeding the admissible limit of 10?4. Most of the received annual effective dose (59.15% of the total) is attributed to 228Ra.
相似文献An experimental investigation on the feasibility and relevance of the tri fuel blends of ethanol and dibutyl ether with diesel was studied to replace pure diesel. The solubility of the ethanol and dibutyl ether with a percentage of 25% and 75% resulted with no phase separation, found miscible and stable with diesel at any percentage. However, the properties such as densities and refractive index experimentally verified for different blend ratios. A density of test samples with various compositions was tested. High precise equipment is engaged to analyze the density, speed of sound, refractive index for various fuel compositions. The temperature ranges between 298 K and 343 K show a greater impact on variation in the fuel properties. Density, speed of sound, refractive indices measured as a function of the temperature with an accuracy of?±?0.001 and?±?0.0001. Further, the validation of experimental method has been tested using Lorentz–Lorenz (L–L) analysis with a deviation of 0.4%. The uncertainty for fluid velocity is?±?0.3 m s?1, and the experimental estimated excess molar volume uncertainty is 2?×?10?3 cm3 mol?1. The substantiation of intermolecular interactions between the liquids is found to be significant in both experimental and prediction analysis of each sample. The exergy destruction specifies with 46% which includes the air flow and chemical heat energy transfer losses.
相似文献The neutron capture cross-sections of 238U at the neutron energies of 4.38?±?0.05 MeV, 3.02?±?0.49 MeV and 2.04?±?0.26 MeV have been measured using the activation method and off-line gamma-ray spectrometric technique. The effects of neutron flux fluctuation, multiple scattering, flux self-shielding and gamma-ray self-absorption were corrected. The excitation function of the 238U(n,γ)239U reaction was also calculated using the TALYS-1.9 code. The experimental results were compared with the evaluated data, the theoretical data and the previous experimental data.
相似文献α-Amylase and α-Glucosidase are important therapeutic targets for type II diabetes. The present focus of our study is to elucidate the hypoglycemic activity of novel compounds through in vitro and in silico studies. Here, we synthesized the nitro acridines (3a–3c), amino acridines (4a–4c), and nitro phenylquinoline (3d) and amino phenylquinoline (4d) using a multi-step reaction protocol in good yields. All the above derivatives were screened for molecular docking, α-Amylase and α-Glucosidase inhibitory activities utilizing acarbose as standard drug. In silico studies were performed to explore the binding ability of compounds with the active site of α-Amylase and α-Glucosidase enzymes. The in vitro antihyperglycemic report of 3c exhibits the maximum inhibitory activity with IC50 values of 200.61?±?9.71 μmol/mL and 197.76?±?8.22 μmol/mL against α-Amylase and α-Glucosidase, respectively. Similarly, the compound 3a exhibits IC50 values of 243.78?±?13.25 μmol/mL and 296.57?±?10.66 μmol/mL, and 4c exhibits IC50 values of 304.28?±?3.51 μmol/mL and 278.86?±?3.24 μmol/mL with a significant p?<?0.05 in both enzyme inhibitions. In addition, the presence of diverse functional moieties in synthesized compounds may provide a strong inhibitory action against the abovementioned enzymes compared with standard acarbose inhibition (IC50, 58.74?±?3.68 μmol/mL and 49.39?±?4.94 μmol/mL). Also, the docking studies provided an excellent support for our in vitro studies. The outcome of these studies recommends that the tested compounds might be treated as potential inhibitors for the starch hydrolyzing enzymes in type II diabetes.
相似文献The present work presented a synthesis of silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) using the aqueous extract of waste banana stem (WBS), Musa paradisiaca Linn. The reduction and formation of MNPs have been characterized by several analysis techniques such as X-ray diffraction (XRD), Fourier transmission infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM). The techniques showed that average particle size of WBS-AgNPs and WBS-AuNPs in crystalline nature was in ranges of 7–13 nm and 11–14 nm, respectively. The synthesized nanoparticles were used to evaluate antibacterial activity and catalysis. The WBS-AgNPs showed strong antibacterial activity against B. subtilis and E. coli. The largest zone of inhibition against B. subtilis (14.2 mm) and E. coli (9.3 mm) was found at concentrations of 4.0 ppm and 2.0 ppm, respectively. The excellent catalytic application of both the nanoparticles for the reduction of 4-nitrophenol was confirmed via study on their kinetics. The normalized kinetic constants (knor) of WBS-AgNPs and WBS-AuNPs were found to be 1.72?×?10–3 s?1 mg?1 and 2.45?×?10–3 s?1 mg?1, respectively.
相似文献Sorption of micro- and microamounts of Sr from seawater has been studied using granulated Na-birnessite. Distribution coefficients of 90Sr in the natural seawater are 0.8–1.2?×?103 ml g?1, in the model seawater they are 1.6–1.8?×?103 ml g?1. Application of Na-birnessite was shown to be prospective in sorption–desorption–regeneration regime. In dynamic sorption conditions, over 150 bed volumes of seawater can be purified till 5% breakthrough occurs at feed rate 10 BV h?1. Na-birnessite can be used for 90Sr radionuclide removal from liquid radioactive wastes containing seawater.
相似文献Molecular dynamics simulation was applied to investigating the evolvement rule of cobalt melt microstructure during solidification at different cooling rates. The cooling rate for the formation of amorphous phase is determined by analyzing the radial distribution function, the H–A bond-type index and the mean square displacement. The simulation results showed that the nucleation undercooling increases with the initial temperature, and in the undercooling versus temperature curve, there are two inflection points. Besides, when the initial temperature reaches 2450 K, the undercooling will be stabilized at 1061 K. As the cooling rate is less than 1.0?×?1011.0 K s?1, the FCC and HCP crystal structures will be obtained. Amorphous structure will be obtained if the cooling rate is more than 1.0?×?1013.0 K s?1. If the cooling rate of the Co melt is between 1.0?×?1011.0 and 1.0?×?1013.0 K s?1, the crystal and amorphous structures will be coexistent, which indicates that the critical cooling rate of crystal–amorphous transition is 1.0?×?1011.0 K s?1.
相似文献Two procyanidin B2 conformers were identified in a relative abundance ratio of approximately 3:1 at 298 K by 1H NMR experiments in acetonitrile. The conformational interchange reactions between these two conformers are 1st order in both reactions, with ?G? for forward and reverse of 57.12?±?5.62 and 54.56?±?5.48 kJ mol?1, respectively. The experimentally obtained standard thermodynamic energies for this reaction are ΔH0rxn (3.67?±?0.22 kJ mol?1), ΔS0rxn (4.05?±?1.57 kJ mol?1 K?1), and ΔH0rxn (2.96?±?0.33 kJ.mol?1). Conformational search results at the DFT (PBE, PBE-D2, and B3LYP with 6-311++g**) level of theory yielded four novel conformations, named fully compact (FC), partially compact (PC), partially extended (PE), and fully extended (FE). Although the FC conformer is electronically the most stable of the four as a result of extensive intramolecular non-covalent interactions, the PC and FE conformers are thermodynamically favored in a 5:1 ratio (B3LYP), with the FC and PE conformers present in negligible amounts at equilibrium. The DFT computed standard reaction energies using the B3LYP functional for the PCmajor to FEminor conformational interchange reaction compare exceptionally well with experimental data at 298 K: ?G0rxn (3.86 kJ mol?1), ΔH0rxn (5.34 kJ mol?1), and ?S0rxn (4.97 kJ mol?1 K?1). It was found that inclusion of solvation energies is crucial to obtain accurate thermodynamic energies. The secondary equilibria found in chromatographic separations are predicted to be highly dependent on solvent polarity and temperature. Similar conformational diversity and hierarchies should exist for all non-rigid procyanidin oligomers and the unique chromatographic behavior of these compounds may be a result of conformational interchange.
相似文献Recombinant human interferon alpha2b (rhIFN-α2b) protein is FDA approved for treatment of many tumors and viral diseases. A rhIFN-α2b isoform has been produced and purified from the refolding reaction using high-resolution anion ion exchange chromatography. This isoform has a proper MW (19 kDa) and high purity and homogeneity. The conservation of native linear and conformational epitopes in this isoform was immunologically confirmed by Western blot and ELISA. Mass spectrometry assessment of its intact mass showed average mass (19,337 Da) equivalent to that of the expressed rhIFN-α2b protein without any chemical modification and without the first methionine. Peptide mapping of rhIFN-α2b through tryptic digestion of reductive/alkylated protein using urea as a denaturing agent gave the best pattern. The rhIFN-α2b had a high specific antiviral activity (2.5?×?108?±?1.1?×?108IU/mg protein). In vivo clearance study of rhIFN-α2b in female SD rats (500 μg/kg, intramuscularly) revealed rapid clearance (elimination half-life 0.54 h with a maximum plasma concentration of 33,792 pg/ml) compared with the commercial rhIFN-α2 (elimination half-life 0.75–0.96 h). In conclusion, the prepared rhIFN-α2b isoform has high purity, homogeneity, native like chemical and structural composition, high antiviral activity, and proper biological stability, which reduce its immunogenicity and raise its therapeutic efficiency.
相似文献In this work, two newly sensitive and selective Al(III)-modified carbon paste electrodes (MCPEs) were developed based on diphenylcarbazone (DPC) modifier mixed with tricresyl phosphate plasticizer and either graphite powder (electrode I) or graphite powder mixed with graphene (electrode II). The potentiometric performance characteristics of the two electrodes were scrutinized and discussed. The proposed sensors showed a high electrochemical response in the linear concentration range of 1.0 × 10−6 to 1.0 × 10−2 mol L−1 with a good Nernstian slopes of 20.12 ± 0.30 mV decade−1 and 20.63 ± 0.66 mV decade−1 and limits of detection of 9.0 × 10−7 and 8.5 × 10−7 mol L−1 for electrode (I) and electrode (II), respectively. Both electrodes showed a fast response time and reasonable thermal stability. The potentiometric response of the DPC-based electrodes was independent on the pH of the tested solutions in ranges of 2.5–5 and 2.5–5.5 for electrode (I) and electrode (II), respectively. The two electrodes can be also used in partially non-aqueous medium containing up to 20% (v/v) acetone or methanol with no significant changes in the working concentration ranges or the slopes. The proposed electrodes showed fairly good discriminating ability toward Al(III) ions in comparison with many other metal ions. The electrodes were applied successfully for Al(III) ions determination in drainage water, spiked tap water and pharmaceutical preparation samples. Furthermore, the electrode surfaces were characterized using energy-dispersive X-ray (EDX) and scanning electron microscopic (SEM) as surface characterization techniques and Fourier Transform Infrared (FT-IR) technique to confirm the interaction between Al(III) and DPC.
相似文献The aim of the present research was to formulate and characterize radioiodinated folic acid-chitosan conjugated thymoquinone nanoparticles (FATQCSNPs) and to increase targeting ability on ovarian cancer cell. The dose of drug-loading into the FATQCSNPs and the amount of folic acid on the FATQCSNPs surface were determined as a 20.0?±?1% and 46.0?±?0.5%, respectively. Cell viabilities (%) determined on SKOV-3 and Caco-2 cells for 48 h. TQ, TQCS and FATQCS were very cytotoxic with lower IC50 values on both cell lines. At specific-activity-dependent incorporation study, the incorporation efficiencies of 131I-FATQCSNPs was higher than that of 131I-TQ on SKOV3 cell lines.
相似文献The present study pertained to biosynthesis, characterization and biomedical application (larvicidal, histopathology, antibacterial, antioxidant and anticancer activity) of Zinc oxide nanoparticles (ZnONPs) from Pleurotus djamor. The synthesized NPs were characterized using spectral and microscopic analyses and further confirmed by UV–Visible spectrophotometer with apeak of 350 nm. The ZnONPs showed strong antioxidant property (DPPH, H2O2 and ABTS+ radical assay) and expressed good larval toxicity against Ae. aegypti and Cx. quinquefasciatus (IVth instar larvae) with the least LC50 and LC90 values (10.1, 25.6 and 14.4, 31.7 mg/l) after 24 h treatment, respectively. We noticed the morphological changes (damaged anal papillae area and the cuticle layers) in the treated larvae. For the antibacterial assay, the highest growth inhibition zone was recorded in C. diphteriae (28.6?±?0.3 mm), followed by P. fluorescens (27?±?0.5 mm) and S. aureus (26.6?±?1.5 mm). The in vitro cytotoxicity assay depicted a significant level of cytotoxic effects (LC50 values 42.26 μg/ml) of ZnONPs against the A549 lung cancer cells, even at low dose. The overall findings of the study suggest that P. djamor had the ability for the biosynthesis of ZnONPs and could act as an alternative biomedical agent for future therapeutic applications in medical avenues.
相似文献Afterglows of mixed gas of N2 and H2(0–2.5%) flowing microwave discharges in a 5 mm diameter tube connected to a 5 L reactor via a tube of 1.8 cm diameter and 50 cm long, have been studied using optical emission spectroscopy. The obtained results at the entrance of the afterglow tube of 1.8 cm diameter: Short time afterglow (SA), (10–3 s) and inside the 5 L reactor: Long time afterglow (LA), (10–2 s) were then compared. It was found that, in N2 at 2 Torr, 0.5 slpm, the active specie density ratios had a constant value of 10–2 for N/N2, but decreased respectively from 10–3 to 10–4 for N2 (X,v?>?13)/N2 and from 10–6 to 10–8 for N+2 /N2. By directly connecting the discharge tube inside the 5 L reactor, the density increases by 10 for N2 (X,v?>?13) and by 102 for N2+ by changing the afterglow from LA(10?2 s) to a SA(10–3 s). Moreover and by adding 1% of H2 to N2, the N/N2 and H/H2 ratios had constant values of 1% and 0.2% respectively. The SA(10–3 s) appeared to be more efficient for surface treatments than the LA (10–2 s).
相似文献The change in the thermodynamic properties of triclosan adsorption on three activated carbons with the different surface chemistry was studied through immersion calorimetry and equilibrium data; the amount adsorbed of triclosan (Q) during calorimetry was determined and correlated with the energy associated with adsorbate–adsorbent interactions in the adsorption process. It was noted that triclosan adsorption capacity decreases with an increase in oxygenated surface groups. For an activated carbon oxidized with HNO3 (OxAC), the amount adsorbed was 8.50?×?10?3 mmol g?1, for a activated carbon without modification (GAC) Q?=?10.3?×?10?3 mmol g?1 and for a activated carbon heated at 1073 K (RAC1073) Q?=?11.4?×?10?3 mmol g?1. The adsorbed amounts were determined by adjusting the isotherms to the Sips model. For the activated carbon RAC1073, the immersion enthalpy (ΔHimm) was greater than those of the other two activated carbons due to the formation of interactions with the solvent (ΔHimmOxAC?=?? 27.3 J g?1?<?ΔHimmGAC?=?? 40.0 J g?1?<?ΔHimm RAC1073?=???60.7 J g?1). The changes in the interaction enthalpy and Gibbs energy are associated with adsorbate–adsorbent interactions and side interactions such as the adsorbate–adsorbate and adsorbate–solvent interactions.
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