2,191 research outputs found
In vitro and ex vivo evaluation of N‐methyl benzilates as potential PET agents for muscarinic receptors
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/90199/1/25802601207_ftp.pd
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Magnetite solubility and phase stability in alkaline media at elevated temperatures
Magnetite, Fe{sub 3}O{sub 4}, is the dominant oxide constituent of the indigenous corrosion layers that form on iron base alloys in high purity, high temperature water. The apparent simultaneous stability of two distinct oxidation states of iron in this metal oxide is responsible for its unique solubility behavior. The present work was undertaken to extend the experimental and theoretical bases for estimating solubilities of an iron corrosion product (Fe{sub 3}O{sub 4}/Fe(OH){sub 2}) over a broader temperature range and in the presence of complexing, pH-controlling reagents. These results indicate that a surface layer of ferrous hydroxide controls magnetite solubility behavior at low temperatures in much the same manner as a surface layer of nickel(II) hydroxide was previously reported to control the low temperature solubility behavior of NiO. The importance of Fe(III) ion complexes implies not only that most previously-derived thermodynamic properties of the Fe(OH){sub 3}{sup {minus}} ion are incorrect, but that magnetite phase stability probably shifts to favor a sodium ferric hydroxyphosphate compound in alkaline sodium phosphate solutions at elevated temperatures. The test methodology involved pumping alkaline solutions of known composition through a bed of Fe{sub 3}O{sub 4} granules and analyzing the emerging solution for Fe. Two pH-controlling reagents were tested: sodium phosphate and ammonia. Equilibria for the following reactions were described in thermodynamic terms: (a) Fe(OH){sub 2}/Fe{sub 3}O{sub 4} dissolution and transformation, (b) Fe(II) and Fe(III) ion hydroxocomplex formation (hydrolysis), (c) Fe(II) ion amminocomplex formation, and (d) Fe(II) and Fe(III) ion phosphatocomplex formation. 36 refs
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Zinc(II) oxide solubility and phase behavior in aqueous sodium phosphate solutions at elevated temperatures
A platinum-lined, flowing autoclave facility is used to investigate the solubility/phase behavior of zinc(II) oxide in aqueous sodium phosphate solutions at temperatures between 290 and 560 K. ZnO solubilities are observed to increase continuously with temperature and phosphate concentration. At higher phosphate concentrations, a solid phase transformation to NaZnPO{sub 4} is observed. NaZnPO{sub 4} solubilities are retrograde with temperature. The measured solubility behavior is examined via a Zn(II) ion hydrolysis/complexing model and thermodynamic functions for the hydrolysis/complexing reaction equilibria are obtained from a least-squares analysis of the data. The existence of two new zinc(II) ion complexes is reported for the first time: Zn(OH){sub 2}(HPO{sub 4}){sup 2{minus}} and Zn(OH){sub 3}(H{sub 2}PO{sub 4}){sup 2{minus}}. A summary of thermochemical properties for species in the systems ZnO-H{sub 2}O and ZnO-Na{sub 2}O-P{sub 2}O{sub 5}-H{sub 2}O is also provided. 21 refs., 10 figs., 7 tabs
HIV testing strategies outside of health care settings in the European Union (EU)/European Economic Area (EEA): a systematic review to inform European Centre for Disease Prevention and Control guidance
Objectives: In recent years, new technologies and new approaches to scale up HIV testing have emerged. The objective of this paper was to synthesize the body of recent evidence on strategies aimed at increasing the uptake and coverage of HIV testing outside of health care settings in the European Union (EU)/European Economic Area (EEA). Methods: Systematic searches to identify studies describing effective HIV testing interventions and barriers to testing were run in five databases (2010–2017) with no language restrictions; the grey literature was searched for similar unpublished studies (2014–2017). Study selection, data extraction and critical appraisal were performed by two independent reviewers following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results: Eighty studies on HIV testing in non-health care settings were identified, the majority set in Northern Europe. Testing was implemented in 65 studies, with men who have sex with men the risk group most often targeted. Testing coverage and positivity/reactivity rates varied widely by setting and population group. However, testing in community and outreach settings was effective at reaching people who had never previously been tested and acceptability of HIV testing, particularly rapid testing, outside of health care settings was found to be high. Other interventions aimed to increase HIV testing identified were: campaigns (n = 8), communication technologies (n = 2), education (n = 3) and community networking (n = 1). Conclusions: This review has identified several strategies with potential to achieve high HIV testing coverage outside of health care settings. However, the geographical spread of studies was limited, and few intervention studies reported before and after data, making it difficult to evaluate the impact of interventions on test coverage
Proposing new variables for the identification of strategic groups in franchising
The identification of strategic groups in the Spanish franchising area is the
main aim of this study. The authors have added some new strategic variables (not
used before) to the study and have classified franchisors between sectors and
distribution strategy. The results reveal the existence of four perfectly differentiated
strategic groups (types of franchisors). One of the major implications of this study is
that the variables that build a strategic group vary depending on the respective sector the network operates in and its distribution strategy. This fact indicates that including sector and distribution strategy is absolutely necessary to achieve good classifications of franchisor type
What Type of Person Would Be Willing to Fly with Children? A Multi-Model Analysis
The purpose of this study was to assess the type of person who would be willing to fly with children in various scenarios.
A quantitative methodology and a non-experimental research approach were used in this study. A two-stage approach created a regression equation then assessed model fit. Six hundred and twenty participants were recruited for the study. The dataset was split randomly into two groups to facilitate the two-stage approach, resulting in 310 participants per stage. The study used 14 possible predictors to determine willingness to fly in five different scenarios.
Five models were created and found between two and four predictors of passengers who were willing to fly with children in various scenarios. We were able to explain between 14.3% and 18.6% of the variance. All five equations were assessed for model fit and found to support a good model fit.
Many aviation studies have examined willingness to fly in various scenarios; however, no research specific to the type of person who would be willing to fly with children has been explored. This study aims to fill that gap by exploring the type of person who would fly with children in five different scenarios
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Development of innovative fuelling systems for fusion energy science
The development of innovative fueling systems in support of magnetic fusion energy, particularly the International Thermonuclear Experimental Reactor (ITER), is described. The ITER fuelling system will use a combination of deuterium-tritium (D-T) gas puffing and pellet injection to achieve and maintain ignited plasmas. This combination will provide a flexible fuelling source with D-T pellets penetrating beyond the separatrix to sustain the ignited fusion plasma and with deuterium-rich gas fuelling the edge region to meet divertor requirements in a process called isotopic fuelling. More advanced systems with potential for deeper penetration, such as multistage pellet guns and compact toroid injection, are also described
The MAJORANA DEMONSTRATOR: A Search for Neutrinoless Double-beta Decay of Germanium-76
The {\sc Majorana} collaboration is searching for neutrinoless double beta
decay using Ge, which has been shown to have a number of advantages in
terms of sensitivities and backgrounds. The observation of neutrinoless
double-beta decay would show that lepton number is violated and that neutrinos
are Majorana particles and would simultaneously provide information on neutrino
mass. Attaining sensitivities for neutrino masses in the inverted hierarchy
region, meV, will require large, tonne-scale detectors with extremely
low backgrounds, at the level of 1 count/t-y or lower in the region of
the signal. The {\sc Majorana} collaboration, with funding support from DOE
Office of Nuclear Physics and NSF Particle Astrophysics, is constructing the
{\sc Demonstrator}, an array consisting of 40 kg of p-type point-contact
high-purity germanium (HPGe) detectors, of which 30 kg will be enriched
to 87% in Ge. The {\sc Demonstrator} is being constructed in a clean
room laboratory facility at the 4850' level (4300 m.w.e.) of the Sanford
Underground Research Facility (SURF) in Lead, SD. It utilizes a compact graded
shield approach with the inner portion consisting of ultra-clean Cu that is
being electroformed and machined underground. The primary aim of the {\sc
Demonstrator} is to show the feasibility of a future tonne-scale measurement in
terms of backgrounds and scalability.Comment: Proceedings for the MEDEX 2013 Conferenc
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