3,265 research outputs found

    Palladium(II)-Catalysed Aminocarbonylation of Terminal Alkynes for the Synthesis of 2-Ynamides: Addressing the Challenges of Solvents and Gas Mixtures

    Get PDF
    2‐Ynamides can be synthesised through Pd(II) catalysed oxidative carbonylation, utilising low catalyst loadings. A variety of alkynes and amines can be used to afford 2‐ynamides in high yields, whilst overcoming the drawbacks associated with previous oxidative methods, which rely on dangerous solvents and gas mixtures. The use of [NBu(4)]I allows the utilisation of the industrially recommended solvent ethyl acetate. O(2) can be used as the terminal oxidant, and the catalyst can operate under safer conditions with low O(2) concentrations

    Exploring the limits of the self consistent Born approximation for inelastic electronic transport

    Full text link
    The non equilibrium Green function formalism is today the standard computational method for describing elastic transport in molecular devices. This can be extended to include inelastic scattering by the so called self-consistent Born approximation (SCBA), where the interaction of the electrons with the vibrations of the molecule is assumed to be weak and it is treated perturbatively. The validity of such an assumption and therefore of the SCBA is difficult to establish with certainty. In this work we explore the limitations of the SCBA by using a simple tight-binding model with the electron-phonon coupling strength α\rm{\alpha} chosen as a free parameter. As model devices we consider Au mono-atomic chains and a H2\rm{H_2} molecule sandwiched between Pt electrodes. In both cases our self-consistent calculations demonstrate a breakdown of the SCBA for large α\rm{\alpha} and we identify a weak and strong coupling regime. For weak coupling our SCBA results compare closely with those obtained with exact scattering theory. However in the strong coupling regime large deviations are found. In particular we demonstrate that there is a critical coupling strength, characteristic of the materials system, beyond which multiple self-consistent solutions can be found depending on the initial conditions in the simulation. We attribute these features to the breakdown of the perturbative expansion leading to the SCBA.Comment: 12 pages, 16 figures, 1 Tabl

    Chiral Symmetry and light resonances in hot and dense matter

    Get PDF
    We present a study of the ππ\pi\pi scattering amplitude in the σ\sigma and ρ\rho channels at finite temperature and nuclear density within a chiral unitary framework. Meson resonances are dynamically generated in our approach, which allows us to analyze the behavior of their associated scattering poles when the system is driven towards chiral symmetry restoration. Medium effects are incorporated in three ways: (a) by thermal corrections of the unitarized scattering amplitudes, (b) by finite nuclear density effects associated to a renormalization of the pion decay constant, and complementarily (c) by extending our calculation of the scalar-isoscalar channel to account for finite nuclear density and temperature effects in a microscopic many-body implementation of pion dynamics. Our results are discussed in connection with several phenomenological aspects relevant for nuclear matter and Heavy-Ion Collision experiments, such as ρ\rho mass scaling vs broadening from dilepton spectra and chiral restoration signals in the σ\sigma channel. We also elaborate on the molecular nature of ππ\pi\pi resonances.Comment: 14 pages, 14 figures. Contribution to Hard Probes 2008, Illa de A Toxa, Spain, June 8th-14th 200

    Biocatalytic and Chemo-Enzymatic Synthesis of Quinolines and 2-Quinolones by Monoamine Oxidase (MAO-N) and Horseradish Peroxidase (HRP) Biocatalysts

    Get PDF
    The oxidative aromatization of aliphatic N-heterocycles is a fundamental organic transformation for the preparation of a diverse array of heteroaromatic compounds. Despite many attempts to improve the efficiency and practicality of this transformation, most synthetic methodologies still require toxic and expensive reagents as well as harsh conditions. Herein, we describe two enzymatic strategies for the oxidation of 1,2,3,4-tetrahydroquinolines (THQs) and N-cyclopropyl-N-alkylanilines into quinolines and 2-quinolones, respectively. Whole cells and purified monoamine oxidase (MAO-N) enzymes were used to effectively catalyze the biotransformation of THQs into the corresponding aromatic quinoline derivatives, while N-cyclopropyl-N-alkylanilines were converted into 2-quinolone compounds through a horseradish peroxidase (HRP)-catalyzed annulation/aromatization reaction followed by Fe-mediated oxidation

    Development and validation of a PROM to capture holistic outcomes in traditional, complementary and integrative medicine - The Warwick Holistic Health Questionnaire (WHHQ-18)

    Get PDF
    Introduction: Existing patient reported outcome measures (PROMs) do not capture all holistic outcomes observed in Traditional, Complementary and Integrative Medicine (TCIM). This study reports development and validation of a PROM to support research on craniosacral therapy (CST) and other TCIMs. Methods: Using a conceptual framework and items developed and evaluated with clients and practitioners in a CST setting, a questionnaire was developed and tested using mixed methods approaches. Evaluation included an iterative process. Psychometric tests: structural validity (exploratory factor analysis, EFA), internal consistency (Cronbach's alpha), convergent validity (correlations with Warwick-Edinburgh Mental Wellbeing Scale, Short Form-12v2 (SF-12), Harry Edwards Healing Impact Questionnaire), repeatability and responsiveness (t-tests; intra class coefficients, ICC). Results: The Warwick Holistic Health Questionnaire (WHHQ-18) was resolved covering mental, physical, emotional and spiritual wellbeing, self-awareness, engaging in life, responsibility for self, living in the moment and satisfaction with life. EFA revealed four correlated sub-scales. Internal reliability was good (alpha = 0.852). Convergent validity showed strong positive correlation with other wellbeing measures, but no correlation with health-related quality of life (SF-12). Repeatability testing showed good agreement (ICC=0.822) and no differences in scores for test-retest (paired t-test: t = 0.355, p = 0.723). Responsiveness analysis showed significant differences in scores (paired t-test t = 6.15, p < 0.001) with 46% of participants having an effect size of 0.5 or more. Conclusion: WHHQ-18 is the first PROM developed for CST practice and captures outcomes important to TCIM more broadly. Good internal consistency, test-retest reliability and responsive at individual and group level make this new PROM an attractive resource for evaluators. Lack of convergent validity with SF-12 scales suggests WHHQ-18 be added to rather than replace HRQol measures in clinical studies

    Galaxy and mass assembly (GAMA) : The wavelength-dependent sizes and profiles of galaxies revealed by MegaMorph

    Get PDF
    We investigate the relationship between colour and structure within galaxies using a large, volume-limited sample of bright, low-redshift galaxies with optical-near-infrared imaging from the Galaxy AndMass Assembly survey.We fit single-component,wavelength-dependent, elliptical SĂ©rsic models to all passbands simultaneously, using software developed by the MegaMorph project. Dividing our sample by n and colour, the recovered wavelength variations in effective radius (Re) and SĂ©rsic index (n) reveal the internal structure, and hence formation history, of different types of galaxies. All these trends depend on n; some have an additional dependence on galaxy colour. Late-type galaxies (nr 2.5), even though they maintain constant n with wavelength, revealing that ellipticals are a superimposition of different stellar populations associated with multiple collapse and merging events. Processes leading to structures with larger Re must be associated with lower metallicity or younger stellar populations. This appears to rule out the formation of young cores through dissipative gas accretion as an important mechanism in the recent lives of luminous elliptical galaxies.Peer reviewe

    East Midlands Research into Ageing Network (EMRAN) Discussion Paper Series

    Get PDF
    Academic geriatric medicine in Leicester . There has never been a better time to consider joining us. We have recently appointed a Professor in Geriatric Medicine, alongside Tom Robinson in stroke and Victoria Haunton, who has just joined as a Senior Lecturer in Geriatric Medicine. We have fantastic opportunities to support students in their academic pursuits through a well-established intercalated BSc programme, and routes on through such as ACF posts, and a successful track-record in delivering higher degrees leading to ACL post. We collaborate strongly with Health Sciences, including academic primary care. See below for more detail on our existing academic set-up. Leicester Academy for the Study of Ageing We are also collaborating on a grander scale, through a joint academic venture focusing on ageing, the ‘Leicester Academy for the Study of Ageing’ (LASA), which involves the local health service providers (acute and community), De Montfort University; University of Leicester; Leicester City Council; Leicestershire County Council and Leicester Age UK. Professors Jayne Brown and Simon Conroy jointly Chair LASA and have recently been joined by two further Chairs, Professors Kay de Vries and Bertha Ochieng. Karen Harrison Dening has also recently been appointed an Honorary Chair. LASA aims to improve outcomes for older people and those that care for them that takes a person-centred, whole system perspective. Our research will take a global perspective, but will seek to maximise benefits for the people of Leicester, Leicestershire and Rutland, including building capacity. We are undertaking applied, translational, interdisciplinary research, focused on older people, which will deliver research outcomes that address domains from: physical/medical; functional ability, cognitive/psychological; social or environmental factors. LASA also seeks to support commissioners and providers alike for advice on how to improve care for older people, whether by research, education or service delivery. Examples of recent research projects include: ‘Local History Café’ project specifically undertaking an evaluation on loneliness and social isolation; ‘Better Visits’ project focused on improving visiting for family members of people with dementia resident in care homes; and a study on health issues for older LGBT people in Leicester. Clinical Geriatric Medicine in Leicester We have developed a service which recognises the complexity of managing frail older people at the interface (acute care, emergency care and links with community services). There are presently 17 consultant geriatricians supported by existing multidisciplinary teams, including the largest complement of Advance Nurse Practitioners in the country. Together we deliver Comprehensive Geriatric Assessment to frail older people with urgent care needs in acute and community settings. The acute and emergency frailty units – Leicester Royal Infirmary This development aims at delivering Comprehensive Geriatric Assessment to frail older people in the acute setting. Patients are screened for frailty in the Emergency Department and then undergo a multidisciplinary assessment including a consultant geriatrician, before being triaged to the most appropriate setting. This might include admission to in-patient care in the acute or community setting, intermediate care (residential or home based), or occasionally other specialist care (e.g. cardiorespiratory). Our new emergency department is the county’s first frail friendly build and includes fantastic facilities aimed at promoting early recovering and reducing the risk of hospital associated harms. There is also a daily liaison service jointly run with the psychogeriatricians (FOPAL); we have been examining geriatric outreach to oncology and surgery as part of an NIHR funded study. We are home to the Acute Frailty Network, and those interested in service developments at the national scale would be welcome to get involved. Orthogeriatrics There are now dedicated hip fracture wards and joint care with anaesthetists, orthopaedic surgeons and geriatricians. There are also consultants in metabolic bone disease that run clinics. Community work Community work will consist of reviewing patients in clinic who have been triaged to return to the community setting following an acute assessment described above. Additionally, primary care colleagues refer to outpatients for sub-acute reviews. You will work closely with local GPs with support from consultants to deliver post-acute, subacute, intermediate and rehabilitation care services. Stroke Medicine 24/7 thrombolysis and TIA services. The latter is considered one of the best in the UK and along with the high standard of vascular surgery locally means one of the best performances regarding carotid intervention
    • 

    corecore