1,326 research outputs found

    An Experience and a Challenge.

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    Cross-National Comparisons of Socioeconomic Differences in Overweight and Obesity

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    Overweight and obesity have become increasingly common in the past decades. Overweight affects 30–80% of adults in Europe. The World Health Organization estimates that 150 million adults in Europe will be obese by 2010. The associated costs with overweight, obesity and related diseases are gargantuan, both from a societal and a financial point of view. One 2002 estimate indicated that the total direct and indirect annual costs of obesity in 15 EU countries may have been as high as € 32.8 billion. Obesity and its associated risks may kill 320 000 men and women annually in Western Europe. The effects on quality of life are more difficult to quantify but are manifold. This raises the question what can be done about it, and how this can be done most effectively. The immediate cause of obesity and overweight is an energy imbalance between calories consumed on one hand, and calories expended on the other hand. But it is overly simplistic to regard overweight and obesity as the result of an imbalance between energy intake and expenditure. Biological susceptibility interacts with a changing environment that includes more sedentary lifestyles and increased dietary abundance. The

    Some asymptotic properties of duplication graphs

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    Duplication graphs are graphs that grow by duplication of existing vertices, and are important models of biological networks, including protein-protein interaction networks and gene regulatory networks. Three models of graph growth are studied: pure duplication growth, and two two-parameter models in which duplication forms one element of the growth dynamics. A power-law degree distribution is found to emerge in all three models. However, the parameter space of the latter two models is characterized by a range of parameter values for which duplication is the predominant mechanism of graph growth. For parameter values that lie in this ``duplication-dominated'' regime, it is shown that the degree distribution either approaches zero asymptotically, or approaches a non-zero power-law degree distribution very slowly. In either case, the approach to the true asymptotic degree distribution is characterized by a dependence of the scaling exponent on properties of the initial degree distribution. It is therefore conjectured that duplication-dominated, scale-free networks may contain identifiable remnants of their early structure. This feature is inherited from the idealized model of pure duplication growth, for which the exact finite-size degree distribution is found and its asymptotic properties studied.Comment: 19 pages, including 3 figure

    Probing metal ion binding and conformational properties of the colicin E9 endonuclease by electrospray ionization time-of-flight mass spectrometry

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    Nano-electrospray ionization time-of-flight mass spectrometry (ESI-MS) was used to study the conformational consequences of metal ion binding to the colicin E9 endonuclease (E9 DNase) by taking advantage of the unique capability of ESI-MS to allow simultaneous assessment of conformational heterogeneity and metal ion binding. Alterations of charge state distributions on metal ion binding/release were correlated with spectral changes observed in far- and near-UV circular dichroism (CD) and intrinsic tryptophan fluorescence. In addition, hydrogen/deuterium (H/D) exchange experiments were used to probe structural integrity. The present study shows that ESI-MS is sensitive to changes of the thermodynamic stability of E9 DNase as a result of metal ion binding/release in a manner consistent with that deduced from proteolysis and calorimetric experiments. Interestingly, acid-induced release of the metal ion from the E9 DNase causes dramatic conformational instability associated with a loss of fixed tertiary structure, but secondary structure is retained. Furthermore, ESI-MS enabled the direct observation of the noncovalent protein complex of E9 DNase bound to its cognate immunity protein Im9 in the presence and absence of Zn2+. Gas-phase dissociation experiments of the deuterium-labeled binary and ternary complexes revealed that metal ion binding, not Im9, results in a dramatic exchange protection of E9 DNase in the complex. In addition, our metal ion binding studies and gas-phase dissociation experiments of the ternary E9 DNase-Zn2+-Im9 complex have provided further evidence that electrostatic interactions govern the gas phase ion stability

    Background Dependent Lorentz Violation: Natural Solutions to the Theoretical Challenges of the OPERA Experiment

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    To explain both the OPERA experiment and all the known phenomenological constraints/observations on Lorentz violation, the Background Dependent Lorentz Violation (BDLV) has been proposed. We study the BDLV in a model independent way, and conjecture that there may exist a "Dream Special Relativity Theory", where all the Standard Model (SM) particles can be subluminal due to the background effects. Assuming that the Lorentz violation on the Earth is much larger than those on the interstellar scale, we automatically escape all the astrophysical constraints on Lorentz violation. For the BDLV from the effective field theory, we present a simple model and discuss the possible solutions to the theoretical challenges of the OPERA experiment such as the Bremsstrahlung effects for muon neutrinos and the pion decays. Also, we address the Lorentz violation constraints from the LEP and KamLAMD experiments. For the BDLV from the Type IIB string theory with D3-branes and D7-branes, we point out that the D3-branes are flavour blind, and all the SM particles are the conventional particles as in the traditional SM when they do not interact with the D3-branes. Thus, we not only can naturally avoid all the known phenomenological constraints on Lorentz violation, but also can naturally explain all the theoretical challenges. Interestingly, the energy dependent photon velocities may be tested at the experiments.Comment: RevTex4, 14 pages, minor corrections, references adde

    Axionic shortcuts for high energy photons

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    We study the photon axion mixing in the presence of large extra dimensions. The eigenvalues and eigenstates of the mixing matrix are analyzed and we establish the resonance condition for the total conversion of a high energy photon into a Kaluza-Klein (KK) axion state. This resonant transition, a photon transformed into a KK axion travelling freely through the bulk and converting back into a photon, may provide a plausible explanation for the transparency of the universe to energetic photons. If the brane we live in is curved, then there are shortcuts through the bulk, which the axion can take. Within our model, the photons having the appropriate resonance energy are using the axionic shortcut and arrive earlier compared to the photons which follow the geodesic on the brane. We suggest that such axionic shortcuts are at the root of the dispersion of time arrival of photons observed by the MAGIC telescope. We indicate also the cosmological significance of the existence of axionic shortcuts for the photon.Comment: 7 page

    High relapse-free survival after preoperative and intraoperative radiotherapy and resection for sulcus superior tumors

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    STUDY OBJECTIVES: Relapse-free survival in patients with sulcus superior tumors. DESIGN: Prospective registration study. SETTING: Department of surgical oncology of a university hospital. PATIENTS: Twenty-one patients treated with preoperative radiotherapy (46 Gy), lobectomy and chest-wall resection, and intraoperative radiotherapy (10 Gy). RESULTS: After a median follow-up of 18 months, 18 patients (85%) were free from locoregional relapse, while 8 patients were still alive. CONCLUSIONS: The results show that this protocol can achieve excellent local tumor control and can even be used for palliative treatment

    Electromagnetic interference prediction in an in-house power-line

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    Abstract —In this paper a new methodology for the prediction of the conducted-emission propagation in an in-house power- line network is presented. This methodology is based on the modal S -parameter characterization of the devices present in the power-line network, as well as on the modal modeling of branch- line connections. The modal S parameters relate common- and di ff erential-mode waves, and give more information regarding interference propagation. With this methodology, common- and di ff erential-mode attenuations, and modal conversion between common and di ff erential modes can be accurately predicted, which is of great interest for power-line communication devel- opment and conducted-emission mitigation. This methodology is tested by accurately predicting the interference levels up to 100 MHz of an in-house power-line network composed by thermal- magnetic circuit breakers, residual-current circuit breakers, single-phase wires and light bulbs.Peer ReviewedPostprint (author’s final draft

    Low serum vitamin D is associated with axial length and risk of myopia in young children

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    The aim of the study was to investigate the relationship between serum 25(OH)D levels and axial length (AL) and myopia in 6-year-old children. A total of 2666 children aged 6 years participating in the birth-cohort study Generation R underwent a stepwise eye examination. First, presenting visual acuity (VA) and AL were performed. Second, automated cycloplegic refraction was measured if LogMAR VA > 0.1. Serum 25-hydroxyvitamin D [25(OH)D] was determined from blood using liquid chromatography/tandem mass spectrometry. Vitamin D related SNPs were determined with a SNP array; outdoor exposure was assessed by questionnaire. The relationships between 25(OH)D and AL or myopia were investigated using linear and logistic regression analysis. Average 25(OH)D concentration was 68.8 nmol/L (SD ± 27.5; range 4–211); average AL 22.35 mm (SD ± 0.7; range 19.2–25.3); and prevalence of myopia 2.3 % (n = 62). After adjustment for covariates, 25(OH)D concentration (per 25 nmol/L) was inversely associated with AL (β −0.043; P < 0.01), and after additional adjusting for time spent outdoors (β −0.038; P < 0.01). Associations were not different between European and non-European children (β −0.037 and β −0.039 respectively). Risk of myopia (per 25 nmol/L) was OR 0.65 (95 % CI 0.46–0.92). None of the 25(OH)D related SNPs showed an association with AL or myopia. Lower 25(OH)D concentration in serum was associated with longer AL and a higher risk of myopia in these young children. This effect appeared independent of outdoor exposure and may suggest a more direct role for 25(OH)D in myopia pathogenesis

    Proteome biology of stem cells

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    AbstractThe notion that integration of cutting-edge technologies in stem cell research would be enhanced by proteomic analyses has emanated from rapid advances in proteome technology. These advances have increased the probability that basic properties of stem cells will be elucidated more effectively, leading to acceleration toward novel stem cell therapies. We have therefore sought to establish a world-wide alliance of proteomics and stem cell researchers, which has resulted in the foundation of an initiative supported by the Human Proteome Organisation (HUPO) and the International Society for Stem Cell Research (ISSCR) called the Proteome Biology of Stem Cells Initiative. Here we report on the rationale and goals of this initiative
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