Kinetic, Spectroscopic, and X-Ray Crystallographic Evidence for the Cooperative Mechanism of the Hydration of Nitriles Catalyzed by a Tetranuclear Ruthenium-μ-oxo-μ-hydroxo Complex

The tetranuclear ruthenium-oxo-hydroxo-hydride complex {[(PCy3)(CO)RuH]4(μ4-O)(μ3-OH)(μ2-OH)} (1) was found to be a highly cooperative catalyst for the nitrile hydration reaction. The cooperative mechanism of the hydration of benzonitrile was established by Hill inhibition kinetics. The treatment of a nitrile substrate with complex 1 led to the catalytically relevant nitrile-coordinated tetraruthenium complex 3. The X-ray structure of the nitrile-coordinated complex 3 showed a considerably “relaxed” tetrameric core structure compared to that of 1. The hydration of para-substituted benzonitriles p-X-C6H4CN with an electron-withdrawing group (X = Cl, Br, CO2H, CF3) exhibited cooperative kinetics, as indicated by the sigmoidal saturation kinetics, while the hydration of nitriles with an electron-donating group (X = OH, OMe, t-Bu, CH3) obeyed Michaelis–Menten saturation kinetics. The formation of a ruthenium hydride species was observed during the hydration of methacrylonitrile, and its monomeric nature was established by using DOSY NMR techniques

5-Acetyl[2.2]paracyclophane

The title compound 5-acetyltricyclo[8.2.2.24,7]hexa-deca-4,6,10,12,13,15-hexaene, C18H18O,is the first example of a mono-π-substituted [2.2]paracyclophane to be structurally characterized. The average bending angles are α = 13.2 and β = 9.9°. The distance between the \u27bottoms\u27 of the practically parallel boat-like benzene nuclei is 3.098(2) Å. The π conjugation between the acetyl group and the substituted benzene cycle is negligible (rotation angle ca 45°) because of steric hindrance

Multielectron Redox Chemistry of Transition Metal Complexes Supported by a Non‐Innocent N3P2 Ligand: Synthesis, Characterization, and Catalytic Properties

A new redox‐active, diarylamido‐based ligand (LN3P2) capable of κ5‐N,N,N,P,P chelation has been used to prepare a series of complexes with the general formula [MII(LN3P2)]X, where M = Fe (1; X = OTf), Co (2; X = ClO4), or Ni (3; X = ClO4). The diarylamido core of monoanionic LN3P2 is derived from bis(2‐amino‐4‐methylphenyl)amine, which undergoes condensation with two equivalents of 2‐(diphenylphosphanyl)benzaldehyde to provide chelating arms with both arylphosphine and imine donors. X‐ray structural, magnetic, and spectroscopic studies indicate that the N3P2 coordination environment generally promotes low‐spin configurations. Three quasi‐reversible redox couples between +1.0 and –1.5 V (vs. Fc+/Fc) were observed in voltammetric studies of each complex, corresponding to MII/MIII oxidation, LN3P2‐based oxidation, and MII/MI reduction (in order of highest to lowest potential). Spectroscopic and computational analyses of 3ox – generated via chemical one‐electron oxidation of 3 – revealed that a stable diarylaminyl radical (LN3P2·) is formed upon oxidation. The ability of the CoII complex (2) to function as an electrocatalyst for H2 generation was evaluated in the presence of weak acids. Moderate activity was observed using 4‐tert‐butylphenol as the proton source at potentials below –2.0 V. The insights gained here will assist in the future design of pentadentate mixed N/P‐based chelates for catalytic processes

Structure of 5-nitro-2-tosylaminobenzaldehyde di(morpholin-4-yl)aminal Complex with Carbon Tetrachloride

The 5-nitro-2-tosylaminobenzaldehyde di(morpholin-4-yl)aminal forms a stable complex with carbon tetrachloride in the crystal phase. X-ray structural study of this complex indicates an essentially shortened intermolecular contact of 2.89 Å between the oxygen atom of the nitro group and one of the chlorine atom of the CCI4 molecule. Quantum-chemical calculations by semiempirical AMI method showed that the formation of such complex did not cause considerable decrease of system energy or change of charge distribution in molecules. It was supposed that this associate has van der Waals character

Advancing the business and human rights agenda: Dialogue, empowerment, and constructive engagement

As corporations are going global, they are increasingly confronted with human rights challenges. As such, new ways to deal with human rights challenges in corporate operations must be developed as traditional governance mechanisms are not always able to tackle them. This article presents five different views on innovative solutions for the relationships between business and human rights that all build on empowerment, dialogue and constructive engagement. The different approaches highlight an emerging trend toward a more active role for corporations in the protection of human rights. The first examines the need for enhanced dialogue between corporations and their stakeholders. The next three each examine a different facet of empowerment, a critical factor for the respect and protection of human rights: empowerment of the poor, of communities, and of consumers. The final one presents a case study of constructive corporate engagement in Myanmar (Burma). Altogether, these research projects provide insight into the complex relationships between corporate operations and human rights, by highlighting the importance of stakeholder dialogue and empowerment. All the five projects were presented during the Second Swiss Master Class in Corporate Social Responsibility, held in Lausanne, Switzerland on December 12, 2008. The audience for this conference, which examined business and human rights, was composed of researchers, governmental representatives, and business and non-governmental organization practitioners

Assistance tactile à la localisation de cibles périphériques pour des personnes à vision tubulaire

International audienceLa vision tubulaire est une déficience visuelle dans laquelle seul le champ central de la vision est préservé. Elle génère de grandes difficultés dans la vie quotidienne, notamment lorsqu’il s’agit de repérer un objet d’intérêt dans l’environnement. Des informations tactiles, considérées comme discrètes, personnelles et peu invasives, peuvent permettre d’améliorer le comportement de recherche visuelle. Dans cette étude, nous avons conçu quatre techniques tactiles permettant de localiser un point spécifique dans l’espace. Les stimulations tactiles étaient soit un seul stimulus soit un train de stimuli transmis dans un système de coordonnées cartésien ou polaire. Les quatre techniques ont été comparées dans une tâche d’orientation de la tête. La plus efficace des techniques a été évaluée avec une tâche de recherche visuelle dans un environnement virtuel complexe. L’évaluation impliquait dix sujets avec un champ visuel artificiellement restreint à 10°, et un sujet avec une vision tubulaire due à un glaucome. Notre dispositif d’assistance a significativement amélioré l’efficacité de la recherche visuelle d’un facteur trois. Le dispositif pourrait être facilement intégré dans des lunettes intelligentes et détecter des cibles d’intérêt, soit sur demande, soit de façon automatique (par ex. les obstacles potentiels), facilitant ainsi, la recherche visuelle et la perception spatiale de l’environnement

PO-0891: Clinical implementation and experience with real-time anatomy tracking and gating during MR-IGRT

Cardiolog

Mangroves enhance the biomass of coral reef fish communities in the Caribbean

Mangrove forests are one of the world's most threatened tropical ecosystems with global loss exceeding 35% (ref. 1). Juvenile coral reef fish often inhabit mangroves, but the importance of these nurseries to reef fish population dynamics has not been quantified. Indeed, mangroves might be expected to have negligible influence on reef fish communities: juvenile fish can inhabit alternative habitats and fish populations may be regulated by other limiting factors such as larval supply or fishing. Here we show that mangroves are unexpectedly important, serving as an intermediate nursery habitat that may increase the survivorship of young fish. Mangroves in the Caribbean strongly influence the community structure of fish on neighbouring coral reefs. In addition, the biomass of several commercially important species is more than doubled when adult habitat is connected to mangroves. The largest herbivorous fish in the Atlantic, Scarus guacamaia, has a functional dependency on mangroves and has suffered local extinction after mangrove removal. Current rates of mangrove deforestation are likely to have severe deleterious consequences for the ecosystem function, fisheries productivity and resilience of reefs. Conservation efforts should protect connected corridors of mangroves, seagrass beds and coral reefs

Adventitial lymphatic capillary expansion impacts on plaque T cell accumulation in atherosclerosis

During plaque progression, inflammatory cells progressively accumulate in the adventitia, paralleled by an increased presence of leaky vasa vasorum. We here show that next to vasa vasorum, also the adventitial lymphatic capillary bed is expanding during plaque development in humans and mouse models of atherosclerosis. Furthermore, we investigated the role of lymphatics in atherosclerosis progression. Dissection of plaque draining lymph node and lymphatic vessel in atherosclerotic ApoE(-/-)mice aggravated plaque formation, which was accompanied by increased intimal and adventitial CD3(+) T cell numbers. Likewise, inhibition of VEGF-C/D dependent lymphangiogenesis by AAV aided gene transfer of hVEGFR3-Ig fusion protein resulted in CD3(+) T cell enrichment in plaque intima and adventitia. hVEGFR3-Ig gene transfer did not compromise adventitial lymphatic density, pointing to VEGF-C/D independent lymphangiogenesis. We were able to identify the CXCL12/CXCR4 axis, which has previously been shown to indirectly activate VEGFR3, as a likely pathway, in that its focal silencing attenuated lymphangiogenesis and augmented T cell presence. Taken together, our study not only shows profound, partly CXCL12/CXCR4 mediated, expansion of lymph capillaries in the adventitia of atherosclerotic plaque in humans and mice, but also is the first to attribute an important role of lymphatics in plaque T cell accumulation and development.Peer reviewe