503 research outputs found

    Specialty Programs Earn High Marks

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    What\u27s so special about the School of Law\u27s specialty programs? Is it A) they are nationally acclaimed, B) they attract top-notch students and faculty, C) they provide representation for those who can\u27t afford to hire an attorney, or D) all of the above

    Impact of The Daily Mile on children's physical and mental health, and educational attainment in primary schools: iMprOVE cohort study protocol

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    INTRODUCTION: School-based active mile initiatives such as The Daily Mile (TDM) are widely promoted to address shortfalls in meeting physical activity recommendations. The iMprOVE Study aims to examine the impact of TDM on children's physical and mental health and educational attainment throughout primary school. METHODS AND ANALYSIS: iMprOVE is a longitudinal quasi-experimental cohort study. We will send a survey to all state-funded primary schools in Greater London to identify participation in TDM. The survey responses will be used for non-random allocation to either the intervention group (Daily Mile schools) or to the control group (non-Daily Mile schools). We aim to recruit 3533 year 1 children (aged 5-6 years) from 77 primary schools and follow them up annually until the end of their primary school years. Data collection taking place at baseline (children in school year 1) and each primary school year thereafter includes device-based measures of moderate-to-vigorous physical activity (MVPA) and questionnaires to measure mental health (Strengths and Difficulties Questionnaire) and educational attainment (ratings from 'below expected' to 'above expected levels'). The primary outcome is the mean change in MVPA minutes from baseline to year 6 during the school day among the intervention group compared with controls. We will use multilevel linear regression models adjusting for sociodemographic data and participation in TDM. The study is powered to detect a 10% (5.5 min) difference between the intervention and control group which would be considered clinically significant. ETHICS AND DISSEMINATION: Ethics has been approved from Imperial College Research Ethics Committee, reference 20IC6127. Key findings will be disseminated to the public through research networks, social, print and media broadcasts, community engagement opportunities and schools. We will work with policy-makers for direct application and impact of our findings

    Exploring the Limits of Dative Boratrane Bonding: Iron as a Strong Lewis Base in Low-Valent Non-Heme Iron-Nitrosyl Complexes

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    We previously reported the synthesis and preliminary characterization of a unique series of low-spin (ls) {FeNO}āøā»Ā¹ā° complexes supported by an ambiphilic trisphosphineborane ligand, [Fe(TPB)(NO)]^(+/0/āˆ’). Herein, we use advanced spectroscopic techniques and density functional theory (DFT) calculations to extract detailed information as to how the bonding changes across the redox series. We find that, in spite of the highly reduced nature of these complexes, they feature an NO+ ligand throughout with strong Feāˆ’NO Ļ€-backbonding and essentially closed-shell electronic structures of their FeNO units. This is enabled by an Feāˆ’B interaction that is present throughout the series. In particular, the most reduced [Fe(TPB)(NO)]āˆ’ complex, an example of a ls-{FeNO}Ā¹ā° species, features a true reverse dative Fe ā†’ B bond where the Fe center acts as a strong Lewis-base. Hence, this complex is in fact electronically similar to the ls-{FeNO}āø system, with two additional electrons ā€œstoredā€ on site in an Feāˆ’B single bond. The outlier in this series is the ls-{FeNO}ā¹ complex, due to spin polarization (quantified by pulse EPR spectroscopy), which weakens the Feāˆ’NO bond. These data are further contextualized by comparison with a related Nā‚‚ complex, [Fe(TPB)(Nā‚‚)]ā», which is a key intermediate in Fe(TPB)-catalyzed Nā‚‚ fixation. Our present study finds that the Fe ā†’ B interaction is key for storing the electrons needed to achieve a highly reduced state in these systems, and highlights the pitfalls associated with using geometric parameters to try to evaluate reverse dative interactions, a finding with broader implications to the study of transition metal complexes with boratrane and related ligands

    Electronic Structures of an [Fe(NNR_2)]^(+/0/ā€“) Redox Series: Ligand Noninnocence and Implications for Catalytic Nitrogen Fixation

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    The intermediacy of metalā€“NNH_2 complexes has been implicated in the catalytic cycles of several examples of transition-metal-mediated nitrogen (N_2) fixation. In this context, we have shown that triphosphine-supported Fe(N_2) complexes can be reduced and protonated at the distal N atom to yield Fe(NNH_2) complexes over an array of charge and oxidation states. Upon exposure to further H^+/e^ā€“ equivalents, these species either continue down a distal-type Chatt pathway to yield a terminal iron(IV) nitride or instead follow a distal-to-alternating pathway resulting in Nā€“H bond formation at the proximal N atom. To understand the origin of this divergent selectivity, herein we synthesize and elucidate the electronic structures of a redox series of Fe(NNMe_2) complexes, which serve as spectroscopic models for their reactive protonated congeners. Using a combination of spectroscopies, in concert with density functional theory and correlated ab initio calculations, we evidence one-electron redox noninnocence of the ā€œNNMe_2ā€ moiety. Specifically, although two closed-shell configurations of the ā€œNNR_2ā€ ligand have been commonly considered in the literatureā€”isodiazene and hydrazido(2āˆ’)ā€”we provide evidence suggesting that, in their reduced forms, the present iron complexes are best viewed in terms of an open-shell [NNR_2]^ā€¢ā€“ligand coupled antiferromagnetically to the Fe center. This one-electron redox noninnocence resembles that of the classically noninnocent ligand NO and may have mechanistic implications for selectivity in N_2 fixation activity

    Exploring the Limits of Dative Boratrane Bonding: Iron as a Strong Lewis Base in Low-Valent Non-Heme Iron-Nitrosyl Complexes

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    We previously reported the synthesis and preliminary characterization of a unique series of low-spin (ls) {FeNO}āøā»Ā¹ā° complexes supported by an ambiphilic trisphosphineborane ligand, [Fe(TPB)(NO)]^(+/0/āˆ’). Herein, we use advanced spectroscopic techniques and density functional theory (DFT) calculations to extract detailed information as to how the bonding changes across the redox series. We find that, in spite of the highly reduced nature of these complexes, they feature an NO+ ligand throughout with strong Feāˆ’NO Ļ€-backbonding and essentially closed-shell electronic structures of their FeNO units. This is enabled by an Feāˆ’B interaction that is present throughout the series. In particular, the most reduced [Fe(TPB)(NO)]āˆ’ complex, an example of a ls-{FeNO}Ā¹ā° species, features a true reverse dative Fe ā†’ B bond where the Fe center acts as a strong Lewis-base. Hence, this complex is in fact electronically similar to the ls-{FeNO}āø system, with two additional electrons ā€œstoredā€ on site in an Feāˆ’B single bond. The outlier in this series is the ls-{FeNO}ā¹ complex, due to spin polarization (quantified by pulse EPR spectroscopy), which weakens the Feāˆ’NO bond. These data are further contextualized by comparison with a related Nā‚‚ complex, [Fe(TPB)(Nā‚‚)]ā», which is a key intermediate in Fe(TPB)-catalyzed Nā‚‚ fixation. Our present study finds that the Fe ā†’ B interaction is key for storing the electrons needed to achieve a highly reduced state in these systems, and highlights the pitfalls associated with using geometric parameters to try to evaluate reverse dative interactions, a finding with broader implications to the study of transition metal complexes with boratrane and related ligands

    Making the user more efficient: Design for sustainable behaviour

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    User behaviour is a significant determinant of a productā€™s environmental impact; while engineering advances permit increased efficiency of product operation, the userā€™s decisions and habits ultimately have a major effect on the energy or other resources used by the product. There is thus a need to change usersā€™ behaviour. A range of design techniques developed in diverse contexts suggest opportunities for engineers, designers and other stakeholders working in the field of sustainable innovation to affect usersā€™ behaviour at the point of interaction with the product or system, in effect ā€˜making the user more efficientā€™. Approaches to changing usersā€™ behaviour from a number of fields are reviewed and discussed, including: strategic design of affordances and behaviour-shaping constraints to control or affect energyor other resource-using interactions; the use of different kinds of feedback and persuasive technology techniques to encourage or guide users to reduce their environmental impact; and context-based systems which use feedback to adjust their behaviour to run at optimum efficiency and reduce the opportunity for user-affected inefficiency. Example implementations in the sustainable engineering and ecodesign field are suggested and discussed

    Electron Capture Dissociation Mass Spectrometry of Tyrosine Nitrated Peptides

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    In vivo protein nitration is associated with many disease conditions that involve oxidative stress and inflammatory response. The modification involves addition of a nitro group at the position ortho to the phenol group of tyrosine to give 3-nitrotyrosine. To understand the mechanisms and consequences of protein nitration, it is necessary to develop methods for identification of nitrotyrosine-containing proteins and localization of the sites of modification.Here, we have investigated the electron capture dissociation (ECD) and collision-induced association (CID) behavior of 3-nitrotyrosine-containing peptides. The presence of nitration did not affect the CID behavior of the peptides. For the doubly-charged peptides, addition of nitration severely inhibited the production of ECD sequence fragments. However, ECD of the triply-charged nitrated peptides resulted in some singly-charged sequence fragments. ECD of the nitrated peptides is characterized by multiple losses of small neutral species including hydroxyl radicals, water and ammonia. The origin of the neutral losses has been investigated by use of activated ion (AI) ECD. Loss of ammonia appears to be the result of non-covalent interactions between the nitro group and protonated lysine side-chains
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