1,443 research outputs found

    The Correlation of Dyslipidemia with the Extent of Coronary Artery Disease in the Multiethnic Study of Atherosclerosis.

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    BackgroundThe extent of coronary artery calcium (CAC) improves cardiovascular disease (CVD) risk prediction. The association between common dyslipidemias (combined hyperlipidemia, simple hypercholesterolemia, metabolic Syndrome (MetS), isolated low high-density lipoprotein cholesterol, and isolated hypertriglyceridemia) compared with normolipidemia and the risk of multivessel CAC is underinvestigated.ObjectivesTo determine whether there is an association between common dyslipidemias compared with normolipidemia, and the extent of coronary artery involvement among MESA participants who were free of clinical cardiovascular disease at baseline.MethodsIn a cross-sectional analysis, 4,917 MESA participants were classified into six groups defined by specific LDL-c, HDL-c, or triglyceride cutoff points. Multivessel CAC was defined as involvement of at least 2 coronary arteries. Multivariate Poisson regression analysis evaluated the association of each group with multivessel CAC after adjusting for CVD risk factors.ResultsUnadjusted analysis showed that all groups except hypertriglyceridemia had statistically significant prevalence ratios of having multivessel CAC as compared to the normolipidemia group. The same groups maintained statistical significance prevalence ratios with multivariate analysis adjusting for other risk factors including Agatston CAC score [combined hyperlipidemia 1.41 (1.06-1.87), hypercholesterolemia 1.55 (1.26-1.92), MetS 1.28 (1.09-1.51), and low HDL-c 1.20 (1.02-1.40)].ConclusionCombined hyperlipidemia, simple hypercholesterolemia, MetS, and low HDL-c were associated with multivessel coronary artery disease independent of CVD risk factors and CAC score. These findings may lay the groundwork for further analysis of the underlying mechanisms in the observed relationship, as well as for the development of clinical strategies for primary prevention

    Preparation of multiwall carbon nanotubes (MWCNTs) stabilised by highly branched hydrocarbon surfactants and dispersed in natural rubber latex nanocomposites

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    The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology.Malaysia Toray Science Foundation (Grant 2012-0138-102-11)National Nanotechnology Directorate Division (Research Grant 2014-0015-102-03)Universiti Pendidikan Sultan Idris (Research Grant 2012-0113-102-01)Malaysia. Ministry of Education (Research Acculturation Grant Scheme. Grant 2013-0001-101-72)JEOL Ltd

    New Physics and CP Violation in Hyperon Nonleptonic Decays

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    The sum of the CP-violating asymmetries A(Lambda_-^0) and A(Xi_-^-) in hyperon nonleptonic decays is presently being measured by the E871 experiment. We evaluate contributions to the asymmetries induced by chromomagnetic-penguin operators, whose coefficients can be enhanced in certain models of new physics. Incorporating recent information on the strong phases in Xi->Lambda pi decay, we show that new-physics contributions to the two asymmetries can be comparable. We explore how the upcoming results of E871 may constrain the coefficients of the operators. We find that its preliminary measurement is already better than the epsilon parameter of K-Kbar mixing in bounding the parity-conserving contributions.Comment: 12 pages, 2 figure

    Spin polarised nuclear matter and its application to neutron stars

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    An equation of state(EOS) of nuclear matter with explicit inclusion of a spin-isospin dependent force is constructed from a finite range, momentum and density dependent effective interaction. This EOS is found to be in good agreement with those obtained from more sophisticated models for unpolarised nuclear matter. Introducing spin degrees of freedom, it is found that at density about 2.5 times the density of normal nuclear matter the neutron matter undergoes a ferromagnetic transition. The maximum mass and the radius of the neutron star agree favourably with the observations. Since finding quark matter rather than spin polarised nuclear matter at the core of neutron stars is more probable, the proposed EOS is also applied to the study of hybrid stars. It is found using the bag model picture that one can in principle describe both the mass and size as well as the surface magnetic field of hybrid stars satisfactorily.Comment: 26 pages, 11 figures available on reques

    Preparation of multiwall carbon nanotubes (MWCNTs) stabilised by highly branched hydrocarbon surfactants and dispersed in natural rubber latex nanocomposites

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    The performance of single-, double- and triple-chain anionic sulphosuccinate surfactants for dispersing multiwall carbon nanotubes (MWNCTs) in natural rubber latex (NR-latex) was studied using a range of techniques, including field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. The conductivities of the nanocomposites were also investigated using four-point probe measurements. Here, MWCNTs were efficiently dispersed in NR-latex with the aid of hyperbranched tri-chain sulphosuccinate anionic surfactants, specifically sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14). This paper highlights that TC14 performs much better than that of the commercially available surfactant sodium dodecyl sulphate (SDS), demonstrating how careful consideration of surfactant architecture leads to improved dispersibility of MWCNTs in NR-latex. The results should be of significant interest for improving nanowiring applications suitable for aerospace-based technology.</p

    Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead.

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    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety 'Mode of Action' framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology

    Close-to-threshold Meson Production in Hadronic Interactions

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    Studies of meson production at threshold in the hadron--hadron interaction began in the fifties when sufficient energies of accelerated protons were available. A strong interdependence between developments in accelerator physics, detector performance and theoretical understanding led to a unique vivid field of physics. Early experiments performed with bubble chambers revealed already typical ingredients of threshold studies, which were superseded by more complete meson production investigations at the nucleon beam facilities TRIUMF, LAMPF, PSI, LEAR and SATURNE. Currently, with the advent of the new cooler rings as IUCF, CELSIUS and COSY the field is entering a new domain of precision and the next step of further progress. The analysis of this new data in the short range limit permits a more fundamental consideration and a quantitative comparison of the production processes for different mesons in the few--body final states. The interpretation of the data take advantage of the fact that production reactions close-to-threshold are characterized by only a few degrees of freedom between a well defined combination of initial and exit channels. Deviations from predictions of phase-space controlled one-meson-exchange models are indications of new and exciting physics. Precision data on differential cross sections, isospin and spin observables -- partly but by no means adequately available -- are presently turning up on the horizon. There is work for the next years and excitement of the physics expected. Here we try to give a brief and at the same time comprehensive overview of this field of hadronic threshold production studies.Comment: 100 pages, Review article to be published in Prog. Part. Nucl. Phys. Vol. 49, issue 1 (2002

    The Test Your Memory cognitive screening tool: sociodemographic and cardiometabolic risk correlates in a population-based study of older British men.

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    OBJECTIVE: This study aimed to examine the association of Test Your Memory (TYM)-defined cognitive impairment groups with known sociodemographic and cardiometabolic correlates of cognitive impairment in a population-based study of older adults. METHODS: Participants were members of the British Regional Heart Study, a cohort across 24 British towns initiated in 1978-1980. Data stemmed from 1570 British men examined in 2010-2012, aged 71-92 years. Sociodemographic and cardiometabolic factors were compared between participants defined as having TYM scores in the normal cognitive ageing, mild cognitive impairment (MCI) and severe cognitive impairment (SCI) groups, defined as ≥46 (45 if ≥80 years of age), ≥33 and <33, respectively. RESULTS: Among 1570 men, 636 (41%) were classified in the MCI and 133 (8%) in the SCI groups. Compared with participants in the normal cognitive ageing category, individuals with SCI were characterized primarily by lower socio-economic position (odds ratio (OR) = 6.15, 95% confidence interval (CI) 4.00-9.46), slower average walking speed (OR = 3.36, 95% CI 2.21-5.10), mobility problems (OR = 4.61, 95% CI 3.04-6.97), poorer self-reported overall health (OR = 2.63, 95% CI 1.79-3.87), obesity (OR = 2.59, 95% CI 1.72-3.91) and impaired lung function (OR = 2.25, 95% CI 1.47-3.45). A similar albeit slightly weaker pattern was observed for participants with MCI. CONCLUSION: Sociodemographic and lifestyle factors as well as adiposity measures, lung function and poor overall health are associated with cognitive impairments in late life. The correlates of cognitive abilities in the MCI and SCI groups, as defined by the TYM, resemble the risk profile for MCI and Alzheimer's disease outlined in current epidemiological models. © 2016 The Authors. International Journal of Geriatric Psychiatry Published by John Wiley & Sons, Ltd

    Multiphoton Quantum Optics and Quantum State Engineering

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    We present a review of theoretical and experimental aspects of multiphoton quantum optics. Multiphoton processes occur and are important for many aspects of matter-radiation interactions that include the efficient ionization of atoms and molecules, and, more generally, atomic transition mechanisms; system-environment couplings and dissipative quantum dynamics; laser physics, optical parametric processes, and interferometry. A single review cannot account for all aspects of such an enormously vast subject. Here we choose to concentrate our attention on parametric processes in nonlinear media, with special emphasis on the engineering of nonclassical states of photons and atoms. We present a detailed analysis of the methods and techniques for the production of genuinely quantum multiphoton processes in nonlinear media, and the corresponding models of multiphoton effective interactions. We review existing proposals for the classification, engineering, and manipulation of nonclassical states, including Fock states, macroscopic superposition states, and multiphoton generalized coherent states. We introduce and discuss the structure of canonical multiphoton quantum optics and the associated one- and two-mode canonical multiphoton squeezed states. This framework provides a consistent multiphoton generalization of two-photon quantum optics and a consistent Hamiltonian description of multiphoton processes associated to higher-order nonlinearities. Finally, we discuss very recent advances that by combining linear and nonlinear optical devices allow to realize multiphoton entangled states of the electromnagnetic field, that are relevant for applications to efficient quantum computation, quantum teleportation, and related problems in quantum communication and information.Comment: 198 pages, 36 eps figure

    Relocating civil society in a politics of civic-driven change

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    Politics is central to development discourse, yet remains peripheral. Over some twenty years, a civil-society narrative has not fulfilled its potential to 'bring politics back in'. Reasons can be found in conceptual confusion, in selectivity in donor thinking, in policies towards civil society and in the growth-driven political economy of NGO-ism. Remedies for the political lacunae are being sought through a focus on rights, citizenship and leadership that show valuable focused progress. This article examines a comprehensive complement to such efforts referred to as civic-driven change (CDC). Originating in a grounded empirical approach, the constituent principles and elements of CDC offer a lens that can both sharpen and deepen insights and advance analysis of socio-political processes. © The Authors 2013. Development Policy Revie
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