Authors:M. Liezers, S. Lehn, K. Olsen, O. Farmer, and Douglas Duckworth
Electrochemically modulated separations (EMS) are shown to be a rapid and selective means of extracting and concentrating
Pu from complex solutions prior to isotopic analysis by inductively coupled plasma mass spectrometry (ICP‐MS). This separation
is performed in a flow injection mode, on‐line with the ICP‐MS. A three‐electrode, flow‐by electrochemical cell is used to
accumulate Pu at an anodized glassy carbon electrode by redox conversion of Pu(III) to Pu (IV&VI). The entire process takes
place in 2% (v/v) (0.46 M) HNO3. No redox chemicals or acid concentration changes are required. Plutonium accumulation and release is redox dependent and
controlled by the applied cell potential. Large transient volumetric concentration enhancements can be achieved. Based on
more negative U(IV) potentials relative to Pu(IV), separation of Pu from uranium is efficient, thereby eliminating uranium
hydride interferences. EMS‐ICP‐MS isotope ratio measurement performance will be presented for femtogram to attogram level
plutonium isotope injections.
Authors:M. Douglas, J. Friese, G. Warren, P. Bachelor, O. Farmer, A. Choiniere, S. Schulte, and C. Aalseth
A project has been undertaken at Pacific Northwest National Laboratory (PNNL) to tailor a series of efficient chemical separations
to allow the rapid quantification of gamma-ray emitting isotopes in mixed fission product (MFP) samples. In support of that
goal, modeling of singles and coincident gamma-ray spectra that would result from various chemical separation strategies has
been performed. These simulated spectra have identified likely instances of spectral interference and have provided an estimate
of the time window available for the detection of radionuclides following various chemical separation schemes. A description
of results to date is presented here, demonstrating the utility of this approach for improved processing and analysis of fission
Authors:R. Payne, S. Schulte, M. Douglas, J. Friese, O. Farmer, and E. Finn
Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry
applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that
the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method
allows parallel processing of many samples in 1.5 h followed by 60 min counting for quantification of 9 radioisotopes of 7
Authors:Douglas L. Cassimiro, Clóvis A. Ribeiro, Jorge M. V. Capela, Marisa S. Crespi, and Marisa V. Capela
Meglumine, (2R,3R,4R,5S)-6-methylaminohexane-1,2,3,4,5-pentol, is a carbohydrate derived from sorbitol in which the hydroxyl group in position one is replaced by a methylamine group. It forms binary adducts with substances having carboxyl groups, which have in common the presence of hydrogen bonding as the main force in the stabilization of these species. During melting, adducts of meglumine with flunixin (2-[[2-methyl-3-(trifluoromethyl)phenyl]amino]pyridine-3-carboxylic acid) polymerize or self-assemble in amorphous supramolecular structures with molecular weights around 2.0 × 105 kDa. DSC curves, in a first heating, show isomorphic transitions where the last one at 137 °C for the flunixin-meglumine adduct originated the supramolecular amorphous polymers with glass transition around 49.5 °C. The kinetic parameters for the thermal decomposition step of the polymers were determined by the Capela-Ribeiro non-linear isoconversional method. From data for the TG curves in nitrogen atmosphere and heating rates of 5, 10, 15, and 20 °C min−1, the Eα and Bα terms could be determined and, consequently, the pre-exponential factor, Aα, as well as the kinetic model, g(α).
Authors:J. Schwantes, R. Addleman, J. Davidson, M. Douglas, D. Meier, O. Mullen, M. Myjak, M. Jones, M. Woodring, B. Johnson, and P. Santschi
We are developing a medium-resolution autonomous in situ gamma detection system for marine and coastal waters. The system
is designed to extract and preconcentrate isotopes of interest from natural waters prior to detection in order to eliminate
signal attenuation of the gamma rays traveling through water and lower the overall background from the presence of naturally
occurring radioactive isotopes (40K and U–Th series radionuclides). Filtration is used to preconcentrate target isotopes residing on suspended particles, while
chemosorption is employed to preferentially extract truly dissolved components from the water column. Used filter and chemosorbent
media will be counted autonomously using two LaBr3 detectors in a near 4-π configuration around the samples. A compact digital pulse processing system, developed in-house and
capable of running in coincidence mode, is used to process the signal from the detectors to a small on-board computer. The
entire system is extremely compact (9″ dia. × 30″ len.) and platform independent, but designed for initial deployment on a
research buoy. A variety of commercial and in-house nano-porous chemosorbents have been selected, procured or produced, and
these and filter and detector components have been tested.
Authors:Marcelo Kobelnik, Douglas Lopes Cassimiro, Clóvis. A. Ribeiro, Jorge M. V. Capela, Diogines S. Dias, and Marisa S. Crespi
The thermal behaviour of Mg-diclofenac compound was evaluated by simultaneous TG-DTA and DSC. The profile of the DSC curves showed that this compound possesses two transition phases: endothermic and exothermic between 170–180 °C and 185–195 °C, respectively. The endothermic reaction is reversible (enantiotropic). Thus, different experimental conditions, i.e. masses sample, open and crimped lids crucible, static and dynamic atmospheres were utilized for DSC analysis for evaluation of this transition phase. In a static atmosphere the enantiotropic reaction was not observed. The obtained data were utilized to obtain the kinetic parameters, which were calculated by the Capela and Ribeiro method. The results show that the activation energy for the transition phase depends on the different experimental conditions.
Authors:R. Brodzinski, R. Runkle, J. Hartman, E. Ashbaker, M. Douglas, D. Jordan, K. McCormick, W. Sliger, and L. Todd
Migration of groundwater contamination from beneath the Hanford Site into the Columbia River creates a need for in situ 90Sr monitoring. The prototype monitor discussed here was designed for deployment downwell and provides near-real-time determination
of the 90Sr concentration in a two-liter groundwater sample. This manuscript discusses the design, construction and preliminary results
for a prototype monitor. Calibration and testing results of the as-built system show qualitative agreement between simulated
predictions and experimental results. Downwell and laboratory tests demonstrate a sensitivity to 90Sr at concentrations below 8 pCi/l (0.3 Bq/1) at a 90% confidence level in measurement times of less than four hours.
Authors:M. Douglas, J. Friese, L. Greenwood, O. Farmer, M. Thomas, T. Maiti, E. Finn, S. Garofoli, P. Gassman, M. Huff, S. Schulte, S. Smith, K. Thomas, and P. Bachelor
Quantitative measurement of fission and activation products resulting from neutron irradiation of fissile materials is of
interest for applications in environmental monitoring, nuclear waste management, and national security. Based on established
separation processes involving co-precipitation, solvent extraction, and ion-exchange and extraction chromatography, we have
optimized a proposed sequence of separation steps to allow for the timely quantification of analytes of interest. We have
recently evaluated this scheme using an irradiated sample to examine the adequacy of separations for measurement of desired
analytes by gamma spectrometry. Here we present the radiochemical separations utilized and the yields and purity obtained.
Authors:Ana Luiza Ribeiro de Souza, Tatiana Andreani, Fernando M. Nunes, Douglas Lopes Cassimiro, Adélia Emília de Almeida, Clóvis Augusto Ribeiro, Victor Hugo Vitorino Sarmento, Maria Palmira Daflon Gremião, Amélia M. Silva, and Eliana B. Souto
Praziquantel (PZQ) is the drug of choice for oral treatment of schistosomiasis and other fluke infections that affect humans. Its low oral bioavailability demands the development of innovative strategies to overcome the first pass metabolism. In this article, solid lipid nanoparticles loaded with PZQ (PZQ-SLN) were prepared by a modified oil-in-water microemulsion method selecting stearic acid as lipid phase after solubility screening studies. The mean particle size (Z-Ave) and zeta potential (ZP) were 500 nm and −34.0 mV, respectively. Morphology and shape of PZQ-SLN were analysed by scanning electron microscopy revealing the presence of spherical particles with smooth surface. Differential scanning calorimetry suggested that SLN comprised a less ordered arrangement of crystals and the drug was molecularly dispersed in the lipid matrix. No supercooled melts were detected. The entrapment efficiency (EE) and loading capacity of PZQ, determined by high performance liquid chromatography, were 99.06 ± 0.3 and 17.48 ± 0.05, respectively. Effective incorporation of PZQ into the particles was confirmed by small angle X-ray scattering revealing the presence of a lipid lamellar structure. Stability parameters of PZQ-SLN stored at room temperature (25 °C) and at 4 °C were checked by analysing Z-Ave, ZP and the EE for a period of 60 days. Results showed a relatively long-term physical stability after storage at 4 °C, without drug expulsion.
Authors:Hans-Jürgen Rumpf, Sophia Achab, Joël Billieux, Henrietta Bowden-Jones, Natacha Carragher, Zsolt Demetrovics, Susumu Higuchi, Daniel L. King, Karl Mann, Marc Potenza, John B. Saunders, Max Abbott, Atul Ambekar, Osman Tolga Aricak, Sawitri Assanangkornchai, Norharlina Bahar, Guilherme Borges, Matthias Brand, Elda Mei-Lo Chan, Thomas Chung, Jeff Derevensky, Ahmad El Kashef, Michael Farrell, Naomi A. Fineberg, Claudia Gandin, Douglas A. Gentile, Mark D. Griffiths, Anna E. Goudriaan, Marie Grall-Bronnec, Wei Hao, David C. Hodgins, Patrick Ip, Orsolya Király, Hae Kook Lee, Daria Kuss, Jeroen S. Lemmens, Jiang Long, Olatz Lopez-Fernandez, Satoko Mihara, Nancy M. Petry, Halley M. Pontes, Afarin Rahimi-Movaghar, Florian Rehbein, Jürgen Rehm, Emanuele Scafato, Manoi Sharma, Daniel Spritzer, Dan J. Stein, Philip Tam, Aviv Weinstein, Hans-Ulrich Wittchen, Klaus Wölfling, Daniele Zullino, and Vladimir Poznyak
The proposed introduction of gaming disorder (GD) in the 11th revision of the International Classification of Diseases (ICD-11) developed by the World Health Organization (WHO) has led to a lively debate over the past year. Besides the broad support for the decision in the academic press, a recent publication by van Rooij et al. (2018) repeated the criticism raised against the inclusion of GD in ICD-11 by Aarseth et al. (2017). We argue that this group of researchers fails to recognize the clinical and public health considerations, which support the WHO perspective. It is important to recognize a range of biases that may influence this debate; in particular, the gaming industry may wish to diminish its responsibility by claiming that GD is not a public health problem, a position which maybe supported by arguments from scholars based in media psychology, computer games research, communication science, and related disciplines. However, just as with any other disease or disorder in the ICD-11, the decision whether or not to include GD is based on clinical evidence and public health needs. Therefore, we reiterate our conclusion that including GD reflects the essence of the ICD and will facilitate treatment and prevention for those who need it.