One-pot synthesis of sulfonic acid functionalized Zr-MOFs for rapid and specific removal of radioactive Ba2.

Efficient decontamination of radioactive Ba2+ is of great significance to human health and environmental safety. Herein, an adsorbent based on the sulfonic acid functionalized Zr-MOF has been successfully developed, which could efficiently decontaminate radioactive Ba2+ with excellent selectivity, recyclability, a high adsorption capacity up to 60.8 mg g-1 as well as a short adsorption kinetic time of less than 5 min. This outstanding adsorption performance is attributed to the strong affinity between Ba2+ and high density -SO3H active sites in MOFs which were introduced by an in situ ligand modification strategy during the assembly of MOFs.

Nuclear data for reactor production of 131Ba and 133Ba.

The newest radioisotope for brachytherapy treatment of prostate cancer is 131Cs (t1/2 = 9.69 d, 100% EC). Generated via electron capture decay of 131Ba (t1/2 = 11.6 d, 100% EC), 131Cs has been used in brachytherapy for prostate cancer since 2004. The 131Ba parent is produced through neutron capture of enriched 130Ba in a nuclear reactor. For large-scale production of 131Ba, an accurate knowledge of production and burnup cross sections of 131Ba are essential. In this paper, we report two group cross sections (thermal and resonance integrals) for 130Ba and 131Ba and a new measure of the half-life of 131Ba. Targets consisting of milligram quantities of enriched 130Ba (∼35%) were irradiated in Oak Ridge National Laboratory's High Flux Isotope Reactor at thermal and resonance neutron fluxes of (1.9-2.1) × 1015 and (5.8-7.0) × 1013 neutrons·cm-2 s-1, respectively, for durations ranging from 3 to 26 days. In addition, cadmium covered samples of 130Ba were irradiated for 1 hour at 12.6% full reactor power (10.7 MW). The yield of 131Ba approaches a saturation value of ∼60 GBq (∼1.6 Ci) per mg of 130Ba for 20 days irradiation at a thermal neutron flux of 1.8 × 1015 n·s-1·cm-2, with a thermal/epithermal ratio of ∼30. Under the above experimental conditions, the two group cross sections of 130Ba are 6.9 ±â€¯0.5 b (thermal, σ0) and 173 ±â€¯7 b (resonance, I0). These values represent the sum of cross sections to metastable and ground states of 131Ba. For 131Ba, the empirically measured thermal cross section is 200 ±â€¯50 b assuming an I0/σ0 of 10. This cross section is reported for the first time. Further, the half-life of 131Ba was remeasured to be 11.657 ±â€¯0.008 d. Lastly, this study also resulted in the co-production of 133Ba (t1/2 = 10.52 y, 100% EC). The experimental yield of 133Ba is ∼370 MBq (∼10 mCi) per mg of 132Ba (thin target) for one cycle irradiation in the High Flux Isotope Reactor, and measured two-group 132Ba cross sections are 7.2 ±â€¯0.2 b and 39.9 ±â€¯1.3 b. These values also represent the sum of cross sections to metastable and ground states of 133Ba.

Volumetric Changes to the Pharynx in Healthy Aging: Consequence for Pharyngeal Swallow Mechanics and Function.

Pharyngeal lumen volume is prone to increase as a consequence of pharyngeal muscle atrophy in aging. Yet, the impact of this on swallowing mechanics and function is poorly understood. We examined the relationship between pharyngeal volume and pharyngeal swallowing mechanics and function in a sample of healthy community-dwelling seniors. Data were collected from 44 healthy seniors (21 male, mean age = 76.9, SD = 7.1). Each participant swallowed 9 boluses of barium (3 × 5 ml thin, 3 × 20 ml thin, 3 × 5 ml nectar). Pharyngeal shortening, pharyngeal constriction, pyriform sinus and vallecular residue were quantified from lateral view videofluorosopic swallowing studies. Pharyngeal lumen volume was captured during an oral breathing task with acoustic pharyngometry. In addition, within-participant measures of strength and anthropometrics were collected. Four linear mixed effects regression models were run to study the relationship between pharyngeal volume and pharyngeal constriction, pharyngeal shortening, pyriform sinus residue, and vallecular residue while controlling for bolus condition, age, sex, and posterior tongue strength. Increasing pharyngeal lumen volume was significantly related to worse constriction and vallecular residue. In general, larger and thicker boluses resulted in worse pharyngeal constriction and residue. Pharyngeal shortening was only significantly related to posterior tongue strength. Our work establishes the utility of acoustic pharyngometry to monitor pharyngeal lumen volume. Increasing pharyngeal lumen volume appears to impact both pharyngeal swallowing mechanics and function in a sample of healthy, functional seniors.

Characterizing the Flow of Thickened Barium and Non-barium Liquid Recipes Using the IDDSI Flow Test.

The use of thickened liquids for dysphagia management has become wide-spread. Videofluoroscopy is commonly used to determine dysphagia severity and to evaluate the effectiveness of interventions, including texture modification, but this requires the use of radio-opaque contrast media. In order for the results of a videofluoroscopy to have validity with respect to confirming swallowing safety and efficiency on different liquid consistencies, it is important to understand the flow characteristics of the contrast media used and how the flow of these stimuli compares to the flow of liquids that are provided outside the assessment context. In this study, we explored the flow characteristics of 20% w/v barium and non-barium stimuli prepared using starch and gum thickeners to reach the slightly, mildly and moderately thick liquid categories defined by the International Dysphagia Diet Standardisation Initiative (IDDSI). Our goal was to identify recipes that would produce stimuli with stable flow properties over a 3 h time frame post mixing. Thickener concentration was titrated to achieve matching flow (i.e., IDDSI Flow Test results within a 1 ml range) across the four stimulus types (non-barium starch, non-barium gum, barium starch, barium gum) within each IDDSI level. The combination of barium and thickeners resulted in further thickening, particularly with starch-based thickening agents. A probe of the influence of refrigeration showed no difference in flow measures between chilled and room temperature stimuli over a 3-h time frame. Overall, recipes with stable flow over three hours were identified for all barium and non-barium liquids tested.

Ammonium molybdophosphate impregnated alumina microspheres as a new generation sorbent for chromatographic 137Cs/(137m)Ba generator.

Barium-137m availed from a (137)Cs/(137m)Ba generator is an attractive industrial radiotracer for liquid flow rate measurement owing to its short half-life (T(1/2)=2.5 min) and emission of highly energetic gamma radiation (E(γ)=661.7 keV). Ammonium molybdophosphate (AMP) impregnated alumina microspheres (AMP-Al(2)O(3)), an engineered form of sorbent material was synthesized by Gel Entrapment Technique (GET). The utility of the material in the preparation of (137)Cs/(137m)Ba generator was evaluated. Various experimental parameters were optimized for efficient retention of (137)Cs and selective elution of (137m)Ba. A chromatographic 0.74 GBq (20 mCi) (137)Cs/(137m)Ba generator was developed using this material and its performance was evaluated for 6 months. Barium-137m could be eluted from the generator using 0.1 M NH(4)NO(3)+0.5 M HNO(3) solution with >80% yield and with acceptable radionuclidic purity suitable for industrial radiotracer investigations.

Gamma spectrum unfolding for a NaI monitor of radioactivity in aquatic systems: experimental evaluations of the minimal detectable activity.

This paper deals with the experimental evaluation of the minimal detectable activity achievable by unfolding the gamma spectra of a NaI monitor. An aquatic monitor initially developed by the Institut des Radio-Eléments (IRE) is used for the application. Unfolding of the spectra is performed with GRAVEL, a UMG package code, on the basis of a response matrix obtained with MCNP5.1.40. Experimental data have been measured at IRE, in a 20m(3) seawater tank, for known activities of (137)Cs mixed with other gamma emitters ((40)K, (133)Ba, (113)Sn and (139)Ce). Deconvolution allows one to reduce the MDA of (137)Cs by an order of magnitude.

Study of activation cross sections of proton induced reactions on barium: Production of 131Ba-->131Cs.

In the frame of a systematic study of charged particle production routes of the therapeutic radioisotope (131)Cs, excitation functions of the (nat)Ba(p,x)(135,132mg)La, (ind135m,cum133m,cum133mg,cum131mg)Ba and (136mg,134mg,132,cum129)Cs reactions were measured in the 30-70 MeV energy range using stacked foil irradiation technique, activation method and gamma spectroscopy. Comparisons with new results of the ALICE-IPPE and EMPIRE-II codes and with existing data obtained with TALYS code are shown. From the measured cross section data integral yields were calculated and compared with experimental integral yield data reported in the literature. Potential use of proton induced reactions on Ba for production of (131)Cs is discussed.