1,902 research outputs found
The Quest for Palladium-Catalysed Alkyl-Nitrogen Bond Formation
Our interest in the development of transition-metal catalysis for the realisation of vicinal diamination reactions of alkenes started about a decade ago. A number of successful transformations in this area have been developed using palladium catalysis. As a challenging aspect of major importance, the palladium-catalysed coupling of alkyl–nitrogen bonds constitutes the second step in diaminations of alkenes. We here discuss the details that led us to consider high-oxidation-state palladium catalysis as a key feature in such C–N bond-forming reactions. This work discusses both our own contributions and the ones from colleagues and combines the discussion of catalytic reactions and stoichiometric control experiments. It demonstrates that reductive alkyl–nitrogen bond formation from palladium(IV) proceeds with a low activation barrier and through a linear transition state of nucleophilic displacement
Substance Use Disorder Treatment Confidentiality Boot Camp
[Excerpt]: INTRODUCTION: The Health Law and Policy Programs at UNH School of Law, Institute for Health Policy and Practice, and the NH Citizens Health Initiative have contracted with several of the New Hampshire Building Capacity for Transformation Delivery System Reform Incentive Payment (DSRIP) Integrated Delivery Networks (IDN) to provide technical assistance to the IDNs as they develop confidentiality tools related to substance use disorder services projects.
A UNH Team assisted the IDNs by providing an educational summary of federal and state confidentiality requirements, focusing on 42 CFR Part 2, and hosting IDN interdisciplinary teams in three Substance Use Disorder (SUD) Treatment Confidentiality Boot Camp sessions providing technical assistance to assist each IDN partner with their SUD confidentiality project goals. The “boot camp” consisted of several guided meetings with assigned homework to follow, leading to the ultimate development of processes, plans, and draft forms and policies to implement Part 2 confidentiality. The process incorporated learning from the Citizens Health Initiative’s existing New Hampshire Behavioral Health Integration Learning Collaborative.
The Project was implemented during half-day working sessions between May 15 – July 30, based upon the availability of IDN interdisciplinary teams and as arranged in collaboration with the IDNs. The IDNs committed to including project leaders with knowledge about and authority to investigate issues regarding projects, patient flow, and privacy. The project teams were multi-disciplinary. IDN participants were encouraged to review issues, forms, and ideas with their individual legal counsel at any point. The technical assistance provided as part of this project is not and does not take the place of legal advice
Brexit and the fracture of the status quo
La salida del Reino Unido de la UniĂłn Europea supone un cambio muy significativo de
las relaciones internacionales en el ámbito europeo con relevancia mundial. El artĂculo se centra en
intentar analizar algunos de los efectos inmediatos que la salida británica de la Unión Europea
supone para la misma, a partir de la fractura del statu quo existente, contradictoria con la tradicional
polĂtica exterior británica. Para ello analiza el concepto de statu quo, y asumiendo su sentido como
equilibrio de poder, se ponen ejemplos de cĂłmo ha sido el eje rector de la polĂtica británica desde
el siglo XVIII, interrumpida con el Brexit. Finalmente se analizan las consecuencias en el statu quo
europeo de la salida de Reino Unido de la UniĂłn y los posibles resultados que tal reconfiguraciĂłn
produce, fundamentalmente el incremento de poder de Alemania. A partir de aquĂ se plantea el
posible incremento de la influencia rusa en el área europea, tomando como referencia el proyecto
de gasoducto Nord Stream, y el perjuicio general para la influencia americana en EuropaThe departure of the United Kingdom from the European Union represents a very
significant change in international relations at the European level with global relevance. The article
focuses on trying to analyze some of the immediate effects that the British exit from the European
Union supposes for the same, from the fracture of the existing status quo, contradictory with the
traditional British foreign policy. To do this, he analyzes the concept of the status quo, and assuming
its meaning as a balance of power, examples are given of how it has been the guiding axis of British
politics since the 18th century, interrupted with Brexit. Finally, the consequences on the European
status quo of the United Kingdom's departure from the Union and the possible results that such
reconfiguration produces, fundamentally the increase in power of Germany, are analyzed. From
here, the possible increase in Russian influence in the European area is proposed, taking the Nord
Stream gas pipeline project as a reference, and the general damage to American influence in Europ
1.5V fully programmable CMOS Membership Function Generator Circuit with proportional DC-voltage control
A Membership Function Generator Circuit (MFGC) with bias supply of 1.5 Volts and independent DC-voltage programmable functionalities is presented. The realization is based on a programmable differential current mirror and three compact voltage-to-current converters, allowing continuous and quasi-linear adjustment of the center position, height, width and slopes of the triangular/trapezoidal output waveforms. HSPICE simulation results of the proposed circuit using the parameters of a double-poly, three metal layers, 0.5 ÎĽm CMOS technology validate the functionality of the proposed architecture, which exhibits a maximum deviation of the linearity in the programmability of 7 %
The Role of Tungsten Chemical State and Boron on Ammonia Formation Using Nâ‚‚-Hâ‚‚ Radiofrequency Discharges
This work aims at investigating the role of tungsten and boron surfaces on ammonia production with N2textendash H2 radiofrequency plasmas at 3 Pa. The experiments combine the analysis of the reaction products and surface chemical environment using mass spectrometry and x-ray photoelectron spectroscopy (XPS). We show that NH3 is formed upon discharges of N2 or H2 after having exposed a tungsten (W) foil to H2 or N2, respectively. A higher amount of ammonia is formed for the N2-then-H2 case, which we explain by the larger number of Eleytextendash Rideal reaction channels for the formation of NH x (s) and the lower surface diffusion barrier for adsorbed hydrogen, calculated using the density functional theory (DFT). As a result, H(s) combines with N(s) or NH x (s) through Langmuirtextendash Hinshelwood at a faster rate than N(s) combines with another N(s). The amount of NH3 formed with N2textendash H2 discharges after conditioning the tungsten foil with H2, N2 or O2 was also investigated. We observed that this pre-conditioning plays no major role on the amount of NH3 detected with the residual gas analyser, albeit a small decrease was observed after H2 contamination. With DFT, the adsorption energies of H on WO3 and W are found to be similar, while the adsorption of N on WO3 is significantly weaker. The similar NH3 concentrations obtained with a clean and oxidized tungsten surface thus suggest that the adsorption of N does not limit the formation rate of ammonia. The production of NH3 on boron was evaluated as well. The boron surface reduced the amount of detected ammonia almost by half. On the one side, a significant amount of H2 was removed from the surface during the Ar cleaning that followed, which suggests a strong retention of hydrogen. On the other side, the XPS data reveals that nitrogen forms strong bonds with boron and impurities on the surface, regardless on whether hydrogen is previously present on the surface or in the plasma volume. The presence of hydrogen in the plasma volume, simultaneously with nitrogen or after nitrogen exposure, is nevertheless necessary for the formation of NH(s) and NH2(s). No NH3(s) was however detected with XPS. The increased retention of both hydrogen and nitrogen on the boron surface may thus hinder the formation of NH3
Influence of shower fluctuations and primary composition on studies of the shower longitudinal development
We study the influence of shower fluctuations, and the possible presence of
different nuclear species in the primary cosmic ray spectrum, on the
experimental determination of both shower energy and the proton air inelastic
cross section from studies of the longitudinal development of atmospheric
showers in fluorescence experiments. We investigate the potential of track
length integral and shower size at maximum as estimators of shower energy. We
find that at very high energy (~10^19-10^20 eV) the error of the total energy
assignment is dominated by the dependence on the hadronic interaction model,
and is of the order of 5%. At lower energy (~10^17-10^18 eV), the uncertainty
of the energy determination due to the limited knowledge of the primary cosmic
ray composition is more important. The distribution of depth of shower maximum
is discussed as a measure of the proton-air cross section. Uncertainties in a
possible experimental measurement of this cross section introduced by intrinsic
shower fluctuations, the model of hadronic interactions, and the unknown
mixture of primary nuclei in the cosmic radiation are numerically evaluated.Comment: 12 pages, 11 figures, 4 table
Anatomia comparativa da madeira das variedades populares da bracatinga (Mimosa scabrella Bentham).
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