Separation of Am(III) from Cm(III) and Eu(III) by electro-spun polystyrene- immobilized CyMe4-BTPhen

The synthesis of a novel 5-(4-vinylphenyl)-CyMe4-BTPhen actinide selective ligand using selenium free synthetic procedures is reported. For the first time, we report the electrospinning of this actinide selective ligand into a polystyrene fiber and investigate its selective removal of Am(III) from Eu(III) and Am(III) from Cm(III). The functionalized fibres demonstrated a separation factor of SFAm/Eu ∼ 57 and a small, but significant separation of SFAm/Cm ∼ 2.9 at 4 M HNO3

Exploring electronic effects on the partitioning of actinides(III) from lanthanides(III) using functionalised bis-triazinyl phenanthroline ligands

The first examples of 4,7-disubstituted 2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzo-triazin-3-yl)-1,10- phenanthroline (CyMe4 -BTPhen) ligands are reported herein. Evaluating the kinetics, selectivity and stoichiometry of actinide(III) and lanthanide(III) radiotracer extractions has provided a mechanistic insight into the extraction process. For the first time, it has been demonstrated that metal ion extraction kinetics can be modulated by backbone functionalisation and a promising new CHON compliant candidate ligand with enhanced metal ion extraction kinetics has been identified. The effects of 4,7- functionalisation on the equilibrium metal ion distribution ratios are far more pronounced than those of 5,6-functionalisation. The complexation of Cm(III) with two of the functionalised ligands was investigated by TRLFS and, at equilibrium, species of 1:2 [M:L] stoichiometry were observed exclusively. A direct correlation between the ELUMO-EHOMO energy gap and metal ion extraction potential is reported, with DFT studies reaffirming experimental findings

Separation of the minor actinides americium(III) and curium(III) by hydrophobic and hydrophilic BTPhen ligands: exploiting differences in their rates of extraction and effective separations at equilibrium

The complexation and extraction of the adjacent minor actinides Am(III) and Cm(III) by both hydrophobic and hydrophilic pre-organized 2,9-bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) ligands has been studied in detail. It has been shown that Am(III) is extracted more rapidly than Cm(III) by the hydrophobic CyMe4-BTPhen ligand into different organic diluents under non-equilibrium extraction conditions, leading to separation factors for Am over Cm (SFAm/Cm) as high as 7.9. Furthermore, the separation of Am(III) from Cm(III) can be tuned through careful choice of the extraction conditions (organic diluent, contact time, mixing speed, ligand concentration). This ‘kinetic’ effect is attributed to the higher presumed kinetic lability of the Am(III) aqua complex towards ligand substitution. A dependence of the Am(III)/Cm(III) selectivity on the structure of the alkyl groups attached to the triazine rings is also observed, and BTPhens bearing linear alkyl groups are less able to separate Am(III) from Cm(III) than CyMe4-BTPhen. Under equilibrium extraction conditions, hydrophilic tetrasulfonated BTPhen ligands complex selectively Am(III) over Cm(III) and prevent the extraction of Am(III) from nitric acid by the hydrophobic O-donor ligand N,N,N’,N’-tetraoctyldiglycolamide (TODGA), giving separation factors for Cm(III) over Am(III) (SFCm/Am) of up to 4.6. These results further underline the utility of the BTPhen ligands for the extremely challenging separation of the chemically similar minor actinides Am(III) and Cm(III) in future processes to close the nuclear fuel cycle

Complexation of lanthanides, actinides and transition metal cations with a 6-(1,2,4-triazin-3-yl)-2,2’:6’,2’’-terpyridine ligand: implications for actinide(III) /lanthanide(III) partitioning

The quadridentate N-heterocyclic ligand 6-(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-2,2’:6’,2’’-terpyridine (CyMe4-hemi-BTBP) has been synthesized and its interactions with Am(III), U(VI), Ln(III) and some transition metal cations have been evaluated by X-ray crystallographic analysis, Am(III)/Eu(III) solvent extraction experiments, UV absorption spectrophotometry, NMR studies and ESI-MS. Structures of the 1:1 complexes with Eu(III), Ce(III) and the linear uranyl (UO22+) ion were obtained by X-ray crystallographic analysis, and showed similar coordination behavior to related BTBP complexes. In methanol, the stability constants of the Ln(III) complexes are slightly lower than those of the analogous quadridentate bis-triazine BTBP ligands, while the stability constant for the Yb(III) complex is higher. 1H NMR titrations and ESI-MS with lanthanide nitrates showed that the ligand forms only 1:1 complexes with Eu(III), Ce(III) and Yb(III), while both 1:1 and 1:2 complexes were formed with La(III) and Y(III) in acetonitrile. A mixture of isomeric chiral 2:2 helical complexes was formed with Cu(I), with a slight preference (1.4:1) for a single directional isomer. In contrast, a 1:1 complex was observed with the larger Ag(I) ion. The ligand was unable to extract Am(III) or Eu(III) from nitric acid solutions into 1-octanol, except in the presence of a synergist at low acidity. The results show that the presence of two outer 1,2,4-triazine rings is required for the efficient extraction and separation of An(III) from Ln(III) by quadridentate N-donor ligand

Hydrophilic sulfonated bis-1,2,4-triazine ligands are highly effective reagents for separating actinides(iii) from lanthanides(iii) via selective formation of aqueous actinide complexes

We report the first examples of hydrophilic 6,6′-bis(1,2,4-triazin-3-yl)-2,2′-bipyridine (BTBP) and 2,9-bis(1,2,4-triazin-3-yl)-1,10-phenanthroline (BTPhen) ligands, and their applications as actinide(III) selective aqueous complexing agents. The combination of a hydrophobic diamide ligand in the organic phase and a hydrophilic tetrasulfonated bis-triazine ligand in the aqueous phase is able to separate Am(III) from Eu(III) by selective Am(III) complex formation across a range of nitric acid concentrations with very high selectivities, and without the use of buffers. In contrast, disulfonated bis-triazine ligands are unable to separate Am(III) from Eu(III) in this system. The greater ability of the tetrasulfonated ligands to retain Am(III) selectively in the aqueous phase than the corresponding disulfonated ligands appears to be due to the higher aqueous solubilities of the complexes of the tetrasulfonated ligands with Am(III). The selectivities for Am(III) complexation observed with hydrophilic tetrasulfonated bis-triazine ligands are in many cases far higher than those found with the polyaminocarboxylate ligands previously used as actinide-selective complexing agents, and are comparable to those found with the parent hydrophobic bis-triazine ligands. Thus we demonstrate a feasible alternative method to separate actinides from lanthanides than the widely studied approach of selective actinide extraction with hydrophobic bis-1,2,4-triazine ligands such as CyMe4-BTBP and CyMe4-BTPhen

Accrediting Graduate Programs in Healthcare Quality and Safety

The number of master\u27s degree programs in healthcare quality and safety (HQS) has increased significantly over the past decade. Academic accreditation provides assurance that educational programs are of a high quality and meet the needs of students, employers, and the general public. Under the guidance of the Commission on Accreditation of Healthcare Management Education, faculty from 9 universities collaborated in the development of criteria and related content domains to be used in the accreditation of graduate programs in HQS. Thirteen content domains were identified. Four of the content domains, safety and error science, improvement science and quality principles, evidence-based practice, and measurement and process improvement are thought to be foundational domains for graduate education in HQS. This article describes the development of the content domains and accompanying standards for accreditation of graduate programs in HQS

A Case Study of Factors Influencing Performance in the Practice Environment

Athletes’ practice environment can influence their competitive performance. The influencing performance factors present in practice are understudied, and the aim of this study was to explore these factors. Using a case-study approach, the authors investigated a basketball practice environment to reveal influencing performance factors. Participants were 15 members of a U.K. Elite Academy Basketball League team based in a sixth-form college (equivalent to American high school age) that included 10 players, 2 coaches, 1 strength and conditioning coach, 1 academic teacher, and the head of sport (mean age 21.8 yr). A case-study approach was adopted to collect data from interviews, focus groups, and direct observations to provide a holistic assessment of the practice environment. Data were analyzed using inductive thematic analysis, which revealed 6 overarching themes: effort, status, individuality, preparation, team drive, and practice vision. Data analysis exposed several themes of influencing performance factors unreported in previous literature, suggesting that practice environments should be viewed as a stand-alone field of investigative enquiry. The results from this study provide a much-needed foray into the psychological influences of practice and give practitioners the opportunity to reflect on the results against their own practice environments.</jats:p

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Vertebrobasilar arterial occlusions in children

Three children with angiographically confirmed, sudden thrombosis involving the vertebro basilar arterial system are presented. Ten previously reported cases are reviewed with particular regard to possible etiologies. Vertebral artery trauma at the atlantoaxial level is suspected as one important cause. Les auteurs rapportent trois cas d'enfants présentant une trombose soudaine du système artériel vertébrobasilaire, confirmée angiographiquement. Ils revoient dix cas antérieurs, en particulier du point de vue éthiologique. Le traumatisme de l'artère vertébrale au niveau de la charnière cervico-occipitale semble être l'une des causes principale. 3 Kinder mit einer angiographisch nachgewiesenen plötzlich aufgetretenen thrombose des vertebro-basilären Systems werden geschildert, gleichzeitig wird ein Überblick über weitere 10 vorher veröffentlichte Fälle gegeben. Diskussion der möglichen Ätiologie. Es wird darauf verwiesen, daß ein Trauma der A. vertebralis in Höhe des atlanto-axialen Gelenkes eine wichtige Ursache sein kann.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46670/1/234_2004_Article_BF00341593.pd