44 research outputs found

    Resonance Features in the Isotopic Branching Ratios for the F + HD Reaction †

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    Mechanism of Producing Metallic Nanoparticles, with an Emphasis on Silver and Gold Nanoparticles, Using Bottom-Up Methods

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    Bottom-up nanoparticle (NP) formation is assumed to begin with the reduction of the precursor metallic ions to form zero-valent atoms. Studies in which this assumption was made are reviewed. The standard reduction potential for the formation of aqueous metallic atoms—E0(Mn+aq/M0aq)—is significantly lower than the usual standard reduction potential for reducing metallic ions Mn+ in aqueous solution to a metal in solid state. E0(Mn+aq/M0solid). E0(Mn+aq/M0aq) values are negative for many typical metals, including Ag and Au, for which E0(Mn+aq/M0solid) is positive. Therefore, many common moderate reduction agents that do not have significantly high negative reduction standard potentials (e.g., hydrogen, carbon monoxide, citrate, hydroxylamine, formaldehyde, ascorbate, squartic acid, and BH4−), and cannot reduce the metallic cations to zero-valent atoms, indicating that the mechanism of NP production should be reconsidered. Both AgNP and AuNP formations were found to be multi-step processes that begin with the formation of clusters constructed from a skeleton of M+-M+ (M = Ag or Au) bonds that is followed by the reduction of a cation M+ in the cluster to M0, to form Mn0 via the formation of NPs. The plausibility of M+-M+ formation is reviewed. Studies that suggest a revised mechanism for the formation of AgNPs and AuNPs are also reviewed

    Plausible Mechanisms of the Fenton-Like Reactions, M = Fe(II) and Co(II), in the Presence of RCO<sub>2</sub><sup>–</sup> Substrates: Are OH<sup>•</sup> Radicals Formed in the Process?

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    DFT calculations concerning the plausible mechanism of Fenton-like reactions catalyzed by Fe­(II) and Co­(II) cations in the presence of carboxylate ligands suggest that hydroxyl radicals are not formed in these reactions. This conclusion suggests that the commonly accepted mechanisms of Fenton-like reactions induced oxidative stress and advanced oxidation processes have to be reconsidered

    Gesundheitsf&ouml;rderung in den Lebenswelten gemeinsam st&auml;rken. Der Kopperationsverbund &quot;Gesundheitliche Chancengleichheit&quot;.

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    BACKGROUND: In 2003, the German Federal Center for Health Education (BZgA) initiated a national Cooperation Network named &quot;Equity in Health&quot; to address scientific results, focusing on the association between social inequalities and health. The main goal is to support setting approaches aimed at reducing these health inequalities. RESULTS AND KEY ACTIVITIES: In the autumn of 2015 the Cooperation Network comprised a total of 65 (institutional) cooperation partners, e.g., from prevention and health promotion, from the medical profession, from the welfare associations, and from the municipal umbrella organziations. The website www.gesundheitliche-chancengleichheit.de was created to present the information available on all activities and structures. Further, Coordination Centers for Health Equity were established in all federal states of Germany to advise, coordinate and provide support for all those who are actively engaged in the key issues for each state. These Coordination Centers are sponsored by the statutory sickness funds and the Health Ministry of the respective states. They also support continuous quality improvement, based on the good practice criteria developed by the Cooperation Network. Since 2011, the local partner process &quot;Health for All&quot; (until November 2015 &quot;Growing Up Healthily for All&quot;) has assisted the municipalities in developing their own integrated health strategies oriented toward the different stages in the life course (&quot;prevention chains&quot;). PERSPECTIVES: The results and structures that have emerged from the Cooperation Network form a good basis for the implementation of the new national Prevention Law passed by German Parliament in July 2015, to expand and develop further, on a country-wide basis and in the various states, living-space-oriented prevention and health promotion consolidating activities. The paper also discusses the present and future challenges of the Cooperation Network

    German cooperation-network &#39;equity in health&#39; - Health promotion in settings.

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    In 2003, the German Federal Centre for Health Education (BZgA) initiated the national Cooperation-Network (CN) &#39;Equity in Health&#39;. The CN is constantly increasing in size and scope, supporting setting approaches aimed at reducing health inequalities. A detailed description of the CN has not yet been available in English. The CN comprises a total of 66 institutional cooperation partners. Information concerning the structure and activities can be found on a special website. Coordination Centres (CC) have been established in the 16 federal states, for the coordination of all state-specific activities. Funding for the CN and CC is provided by the BZgA, the German statutory sickness funds and by the state-specific ministries of health. These partners also support the continuous quality improvement, which is based on the good-practice criteria developed by the Advisory Committee of the CN. In 2011, the &#39;Municipal Partner Process (MPP)&#39; has been launched, specifically supporting local partners and integrated life-course approaches focussing on children. In 2015, the focus has been widened to include all age-groups. In July 2015, a new national health law concerning health promotion and prevention has been ratified by the federal Parliament, with a focus on reducing health inequalities. Currently, the details of its implementation are discussed on a nationwide basis. The CN has long advocated for such a law, and today the CN is a well-accepted partner providing concepts, methods and a strong and long-standing network. The article closes with future challenges faced by the CN

    Harnessing dimethyl ether and methyl formate fuels for direct electrochemical energy conversion

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    In this work, the oxidation of a mixture of dimethyl ether (DME) and methyl formate (MF) was studied in both an aqueous electrochemical cell and a vapor-fed polymer electrolyte membrane fuel cell (PEMFC) utilizing a multi-metallic alloy catalyst, Pt3Pd3Sn2/C, discovered earlier by us. The current obtained during the bulk oxidation of a DME-saturated 1 M MF was higher than the summation of the currents provided by the two fuels separately, suggesting the cooperative effect of mixing these fuels. A significant increase in the anodic charge was realized during oxidative stripping of a pre-adsorbed DME+MF mixture as compared to DME or MF individually. This is ascribed to greater utilization of specific catalytic sites leading to lower energy of the dual-fuel than of the sum of the individual molecules as confirmed by the density functional theory (DFT) calculations. Fuel cell polarization was also conducted using a Pt3Pd3Sn2/C (anode) and Pt/C (cathode) catalysts-coated membrane (CCM). The enhanced surface coverage and active site utilization resulted in providing a higher peak power density by the DME+MF mixture-fed fuel cell (123 mW cm−2 at 0. 45 V) than with DME (84 mW cm−2 at 0.35 V) or MF (28 mW cm−2 at 0.2 V) at the same total anode hydrocarbon flow rate, temperature under ambient pressure
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