59 research outputs found

    Effects of isoflavones (soy phyto-estrogens) on serum lipids: a meta-analysis of randomized controlled trials

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    OBJECTIVES: To determine the effects of isoflavones (soy phyto-estrogens) on serum total cholesterol (TC), low density lipoprotein cholesterol (LDL), high density lipoprotein cholesterol (HDL) and triglyceride (TG). METHODS: We searched electronic databases and included randomized trials with isoflavones interventions in the forms of tablets, isolated soy protein or soy diets. Review Manager 4.2 was used to calculate the pooled risk differences with fixed effects model. RESULTS: Seventeen studies (21 comparisons) with 853 subjects were included in this meta-analysis. Isoflavones tablets had insignificant effects on serum TC, 0.01 mmol/L (95% CI: -0.17 to 0.18, heterogeneity p = 1.0); LDL, 0.00 mmol/L (95% CI: -0.14 to 0.15, heterogeneity p = 0.9); HDL, 0.01 mmol/L (95% CI: -0.05 to 0.06, heterogeneity p = 1.0); and triglyceride, 0.03 mmol/L (95% CI: -0.06 to 0.12, heterogeneity p = 0.9). Isoflavones interventions in the forms of isolated soy protein (ISP), soy diets or soy protein capsule were heterogeneous to combine. CONCLUSIONS: Isoflavones tablets, isolated or mixtures with up to 150 mg per day, seemed to have no overall statistical and clinical benefits on serum lipids. Isoflavones interventions in the forms of soy proteins may need further investigations to resolve whether synergistic effects are necessary with other soy components

    Spin density encodes intramolecular singlet exciton fission in pentacene dimers.

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    The formation of two triplet excitons at the cost of one photon via singlet exciton fission in organic semiconductors can potentially enhance the photocurrent in photovoltaic devices. However, the role of spin density distribution in driving this photophysical process has been unclear until now. Here we present the significance of electronic spin density distribution in facilitating efficient intramolecular singlet exciton fission (iSEF) in π-bridged pentacene dimers. We synthetically modulate the spin density distribution in a series of pentacene dimers using phenyl-, thienyl- and selenyl- flanked diketopyrrolopyrrole (DPP) derivatives as π-bridges. Using femtosecond transient absorption spectroscopy, we find that efficient iSEF is only observed for the phenyl-derivative in ~2.4 ps while absent in the other two dimers. Electronic structure calculations reveal that phenyl-DPP bridge localizes α- and β-spin densities on distinct terminal pentacenes. Upon photoexcitation, a spin exchange mechanism enables iSEF from a singlet state which has an innate triplet pair character

    Lawson criterion for ignition exceeded in an inertial fusion experiment

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    For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

    Excited-State Dynamics in Colloidal Semiconductor Nanocrystals

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    Evaluation of an oral health scoring system by dentists in general dental practice

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    An Oral Health Index (OHX) has been designed to provide a numerical measure of the overall state of a patient's oral health by means of a series of simple clinical examinations. This has been amended to produce the Oral Health Score (OHS). OBJECTIVE: To assess, by means of a questionnaire, the ease of use and understanding of the OHS by general dental practitioners. METHODS: 350 GDPs were asked to participate in the project, of whom 329 agreed. These dentists were given a lecture of 2 hours' duration on the OHS. The participating dentists were requested to use the OHS for a period of 1 year. At the end of this period, a questionnaire was delivered to them by post, with an explanatory letter and reply-paid envelope. RESULTS: Completed, usable questionnaires were received from 239 GDPs, a 77% response rate. Ninety three percent of respondents considered the OHS instructions to be satisfactory. The respondents' views on the criteria on which the OHS component assessments are based indicated that over 90% of respondents agreed with the criteria for caries, adequacy of restorations, periodontal assessment, mucosal assessment and assessment of dentures. A majority of respondents agreed that the OHS provided a valid representation of oral health. CONCLUSION: The results of the present study indicate that the OHS is considered to be an easy-to-use measure of a patient's oral health and that it provides a valid representation of a patient's oral health
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