Synthesis and dosimetric properties of the novel thermoluminescent CaF2:Tm nanoparticles

Calcium fluoride nanoparticles doped with thulium were synthesized for the first time by using the hydrothermal method. The synthesized nanostructures were characterized by X-ray diffraction (XRD) and energy dispersive spectrometer (EDS). The crystallite size of about 40 nm was estimated by Scherer's formula. The shape and size of the nanoparticles were also observed by scanning electron microscope (SEM). T_m–T_stop method and computerized glow curve deconvolution (CGCD) technique were employed to obtain the number of component glow peaks and kinetic parameters of the produced phosphor. Three overlapped thermoluminescence glow peaks were identified at 402, 426 and 467 K in the complex glow curve of this phosphor. The optimized concentration of T_m impurity was obtained at 0.5 mol%. Other thermoluminescence characteristics of this phosphor such as fading, reusability and dose response, reveals superior dosimetry features compared to its microcrystalline counterpart.     

Multiple functions of microfluidic platforms: Characterization and applications in tissue engineering and diagnosis of cancer

Microfluidic system, or lab-on-a-chip, has grown explosively. This system has been used in research for the first time and then entered in the clinical section. Due to economic reasons, this technique has been used for screening of laboratory and clinical indices. The microfluidic system solves some difficulties accompanied by clinical and biological applications. In this review, the interpretation and analysis of some recent developments in microfluidic systems in biomedical applications with more emphasis on tissue engineering and cancer will be discussed. Moreover, we try to discuss the features and functions of microfluidic systems.     

Effects of gamma irradiation on chemical composition and ruminal protein degradation of canola meal

Gamma irradiation of canola meal (at doses of 25, 50 and 75 kGy) could alter its ruminal protein degradation characteristics by cross-linking of the polypeptide chains. This processing resulted in decrease (linear effect, P<0.001) of ruminal protein degradation and increase (linear effect, P<0.001) of intestinal protein digestibility. The results showed that gamma irradiation at doses higher than 25 kGy can be used as a cross-linking agent to improve protein properties of supplements in ruminant nutrition.     

Synthesis and design of polyurethane and its nanocomposites derived from canola-castor oil: Mechanical,thermal and shape memory properties

The recent global pandemic and its tremendous effect on the price fluctuations of crude oil illustrates the side effects of petroleum dependency more evident than ever. Over the past decades, both academic and industrial communities spared endless efforts in order to replace petroleum-based materials with bio-derived resources. In the current study, a series of shape memory polymer composites (SMPC's) was synthesized from epoxidized vegetable oils, namely canola oil and castor oil fatty acids (COFA's) as a 100% bio-based polyol and isophorone diisocyanate (IPDI) as an isocyanate using a solvent/catalyst-free method in order to eventuate polyurethanes (PU's). Thereafter, graphene oxide (GO) nanoplatelets were synthesized and embedded in the neat PU in order to overcome the thermomechanical drawbacks of the neat matrix. The chemical structure of the synthesized components, as well as the dispersion and distribution levels of the nanoparticles, was characterized. In the following, thermal and mechanical properties as well as shape memory behavior of the specimens were comprehensively investigated. Likewise, the thermal conductivity was determined. This study proves that synthesized PU's based on vegetable oil polyols, including graphene nanoparticles, exhibit proper thermal and mechanical properties, which make them stand as a potential candidate to compete with traditional petroleum-based SMPC's.     

Nuclear model calculation on charge particle induced reaction on Rb and Kr targets and targetry for 82Sr production

The ⁸²Sr/⁸²Rb radionuclide generator is used very commonly in positron emission tomography. ALICE/ASH and TALYS 1.0 codes were used to calculate excitation functions for proton, alpha and ³He induced on various targets that lead to produce ⁸²Sr radioisotope using intermediate energy accelerators. Recommended thickness of the targets according to SRIM code was premeditated. The application of those data, particularly in the calculation of integral yields, is discussed and theoretical integral yields for any reaction were computed. To consider precision of TALYS 1.0 code calculations, ⁸⁵Rb(p,4n)⁸²Sr process was determined as most interesting one due to radionuclide purity. The TALYS 1.0 code predicts a maximum cross-section of about 130 mb at 47 MeV for this reaction. Rubidium chloride deposition on copper substrate was carried out via sedimentation method in order to produce ⁸²Sr. 2.98 g RbCl, 1.043 g ethyl cellulose, 10 mL acetone were used to prepare a layer of enriched rubidium chloride of 11.69 cm² area and 0.34 g/cm² thickness.     

Microkinetic simulations of the oxidation of CO on Pd based nanocatalysis: a model including co-dependent support interactions

The catalysed oxidation of CO using mass-selected Pd(13) clusters supported on thin MgO films was modelled using a microkinetic simulation of the reaction. The model of the system includes reverse spill-over calculations which were intrinsically incorporated into the formulation of the kinetics. The spill-over model is based on a capture-zone approach including a co-dependence on the variables of the kinetic equations. The experimental values were determined using dual pulsed-molecular beam measurements and recorded at a range of temperatures. The experiment allowed the turn-over frequency and reaction probability to be determined as a function of mole fraction. Comparison of the kinetic model with the experimental data gives excellent agreement and strongly highlights the importance of substrate effects. In particular, the origin of the low temperature catalysis of the Pd clusters is elucidated. The model allows the mole fraction and temperature dependent values such as the sticking coefficients for these clusters to be predicted.     

Thermodynamics of aqueous solutions of poly ethylene glycol di-methyl ethers in the presence or absence of ammonium phosphate salts

Precise measurements of density and sound velocity at different temperatures ranging from 283.15 to 308.15 K for solutions of PEGDME250, PEGDME500 and PEGDME2000 in water and of PEGDME500 in aqueous solutions of 0.500 mol kg⁻¹ ammonium di-hydrogen phosphate ((NH₄)H₂PO₄) and di-ammonium hydrogen phosphate ((NH₄)₂HPO₄), binodal curves at temperature ranges 293.15-318.15 K for the aqueous PEGDME500 + (NH₄)₂HPO₄, PEGDME500 + (NH₄)₃PO₄, PEGDME2000 + (NH₄)H₂PO₄, PEGDME2000 + (NH₄)₂HPO₄, PEGDME2000 + (NH₄)₃PO₄ and PPG400 + (NH₄)₂HPO₄ two-phase systems, and liquid-liquid equilibrium data at temperature ranges 298.15-318.15 K for the aqueous PEGDME500 + (NH₄)₂HPO₄ and PEGDME2000 + (NH₄)₂HPO₄ two-phase systems have been taken. From the experimental density and sound velocity data, the apparent specific volume, excess specific volume, isentropic compressibility and isentropic compressibility deviation values have been determined and the effect of temperature, charge on the anion of electrolytes and molar mass of PEGDME on the volumetric and compressibility properties of the investigated polymer solutions as well as on the salting-out effect of PEGDMEs produced by ammonium phosphate salts has been studied.     

Synthesis and application of a thermosensitive tri-block copolymer as an efficient sample treatment technique for preconcentration and ultra-trace detection of lead ions

We have designed and synthesized a thermosensitive tri-block copolymer for selective trace extraction of Pb(II) ions from biological and food samples. The polymer was characterized by Fourier transform IR and NMR spectroscopy, and by gel permeation chromatography. The critical aggregation concentration and lower critical solution temperature were determined via fluorescence and UV spectrophotometry, respectively. The effects of solution pH value, amount of copolymer, of the temperature on extraction and on phase separation, and of the matrix on the extraction of Pb(II) were optimized. Pb(II) ions were then quantified by FAAS. The use of this copolymer resulted in excellent figures of merit including a calibration plot extending from 0.5 to 160 μg L^?1 (with an R² of >0.99), a limit of detection (LOD) as low as 90 pg L^?1, an extraction efficiency of >98 %, and relative standard deviations of <4 % for eight separate extraction experiments.