191 research outputs found
Tandem Intramolecular Nicholas and Pauson-Khand Reactions for the Synthesis of Tricyclic Oxygen-Containing Heterocycles
Simple acyclic enynes can be easily converted into tricyclic ethers upon treatment with Co2(CO)8followed by Nicholas and Pauson−Khand reactions. Tricyclic [5,8,5]- and [5,7,5]-systems can be prepared in high overall yields in only seven synthetic steps
An analytical study of seismoelectric signals produced by 1-D mesoscopic heterogeneities
The presence of mesoscopic heterogeneities in fluid-saturated porous rocks
can produce measurable seismoelectric signals due to wave-induced fluid flow
between regions of differing compressibility. The dependence of these signals
on the petrophysical and structural characteristics of the probed rock mass
remains largely unexplored. In this work, we derive an analytical solution to
describe the seismoelectric response of a rock sample, containing a horizontal
layer at its center, that is subjected to an oscillatory compressibility test.
We then adapt this general solution to compute the seismoelectric signature of
a particular case related to a sample that is permeated by a horizontal
fracture located at its center. Analyses of the general and particular
solutions are performed to study the impact of different petrophysical and
structural parameters on the seismoelectric response. We find that the
amplitude of the seismoelectric signal is directly proportional to the applied
stress, to the Skempton coefficient contrast between the host rock and the
layer, and to a weighted average of the effective excess charge of the two
materials. Our results also demonstrate that the frequency at which the maximum
electrical potential amplitude prevails does not depend on the applied stress
or the Skempton coefficient contrast. In presence of strong permeability
variations, this frequency is rather controlled by the permeability and
thickness of the less permeable material. The results of this study thus
indicate that seismoelectric measurements can potentially be used to estimate
key mechanical and hydraulic rock properties of mesoscopic heterogeneities,
such as compressibility, permeability, and fracture compliance.Comment: 14 pages, 8 figure
Prácticas de laboratorio de fisicoquímica de los materiales. -- 3a. edición, 2007.
89 páginas.Contiene 9 prácticas de laboratorio: 1. Volumen molar parcial. -- 2. Procesos con gas ideal. -- 3. Equilibrio líquido-vapor. -- 4. Equilibrio sólido-líquido. -- 5. Equilibrio químico en reacciones homogéneas. -- 6. Constante de disociación. -- 7. Solubilidad. -- 8. Equilibrio metal-ión metálico. -- 9. Cinética química. Al inicio del texto incluye medidas preventivas y correctivas como normas de seguridad
Accounting for Equity Considerations in Cost-Effectiveness Analysis : A Systematic Review of Rotavirus Vaccine in Low- and Middle-Income Countries
Additional file 3: Appendix C. Full data table of results
Counteranion-Dependent Reaction Pathways in the Protonation of Cationic Ruthenium−Vinylidene Complexes
The tetraphenylborate salts of the cationic vinylidene complexes [Cp*Ru=C=CHR(iPr2PNHPy)]+ (R = p-C6H4CF3 (1a-BPh4), Ph (1b-BPh4), p-C6H4CH3 (1c- BPh4), p-C6H4Br (1d-BPh4), tBu (1e-BPh4), H (1f-BPh4)) have been protonated using an excess of HBF4·OEt2 in CD2Cl2, furnishing the dicationic carbyne complexes [Cp*Ru≡CCH2R(iPr2PNHPy)]2+ (R = p-C6H4CF3 (2a), Ph (2b), p-C6H4CH3 (2c), p-C6H4Br (2d), tBu (2e), H (2f)), which were characterized in solution at low temperature by NMR spectroscopy. The corresponding reaction of the chloride salts 1a-Cl, 1b-Cl, 1c-Cl, and 1d-Cl followed a different pathway, instead affording the novel alkene complexes [Cp*RuCl(κ1(N),η2(C,C)-C5H4N-NHPiPr2CH=CHR)][BF4] (3a−d). In these species, the entering proton is located at the α- carbon atom of the former vinylidene ligand, which also forms a P−C bond with the phosphorus atom of the iPr2PNHPy ligand. To shed light on the reaction mechanism, DFT calculations have been performed by considering several protonation sites. The computational results suggest metal protonation followed by insertion. The coordination of chloride to ruthenium leads to alkenyl species which can undergo a P−C coupling to yield the corresponding alkene complexes. The noncoordinating nature of [BPh4]− does not allow the stabilization of the unsaturated species coming from the insertion step, thus preventing this alternative pathway
Advancing tools to promote health equity across European Union regions : The EURO-HEALTHY project
Population health measurements are recognised as appropriate tools to support public health monitoring. Yet, there is still a lack of tools that offer a basis for policy appraisal and for foreseeing impacts on health equity. In the context of persistent regional inequalities, it is critical to ascertain which regions are performing best, which factors might shape future health outcomes and where there is room for improvement. Under the EURO-HEALTHY project, tools combining the technical elements of multi-criteria value models and the social elements of participatory processes were developed to measure health in multiple dimensions and to inform policies. The flagship tool is the Population Health Index (PHI), a multidimensional measure that evaluates health from the lens of equity in health determinants and health outcomes, further divided into sub-indices. Foresight tools for policy analysis were also developed, namely: (1) scenarios of future patterns of population health in Europe in 2030, combining group elicitation with the Extreme-World method and (2) a multi-criteria evaluation framework informing policy appraisal (case study of Lisbon). Finally, a WebGIS was built to map and communicate the results to wider audiences. The Population Health Index was applied to all European Union (EU) regions, indicating which regions are lagging behind and where investments are most needed to close the health gap. Three scenarios for 2030 were produced - (1) the 'Failing Europe' scenario (worst case/increasing inequalities), (2) the 'Sustainable Prosperity' scenario (best case/decreasing inequalities) and (3) the 'Being Stuck' scenario (the EU and Member States maintain the status quo). Finally, the policy appraisal exercise conducted in Lisbon illustrates which policies have higher potential to improve health and how their feasibility can change according to different scenarios. The article makes a theoretical and practical contribution to the field of population health. Theoretically, it contributes to the conceptualisation of health in a broader sense by advancing a model able to integrate multiple aspects of health, including health outcomes and multisectoral determinants. Empirically, the model and tools are closely tied to what is measurable when using the EU context but offering opportunities to be upscaled to other settings
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