190 research outputs found

    The feasibility of wireless capsule endoscopy in detecting small intestinal pathology in children under the age of 8 years: a multicentre European study.

    Get PDF
    Objective: To systematically evaluate the feasibility and methodology to carry out wireless capsule endoscopy (WCE) in children <8 years to define small intestinal pathology. Design: Prospective European multicentre study with negative prior investigation. Patients and interventions: 83 children aged 1.5ā€“7.9 years were recruited. Initially, all were offered ā€œswallowingā€ (Group 1) for capsule introduction. If this failed endoscopic placement (Group 2) was used and the Roth net, Advance or custom-made introducers were compared. Outcome measures: Primary endpoint: to determine pathology; secondary endpoint: comparison of capsule introduction methods. Results: Capsule introduction: 20 (24%) children aged 4.0ā€“7.9 years (mean, 6.9 years; 14 male) comprising Group 1 were older (p<0.025) than 63 (76%) aged 1.5ā€“7.9 years (mean, 5.25 years; 30 male) forming Group 2. Complications: Roth net mucosal trauma in 50%; no others occurred. The available recording apparatus was inappropriate for those <3 years. Indications: gastrointestinal bleeding: nā€Š=ā€Š30 (16 positive findings: four ulcerative jejunitis, four polyps, two angiodysplasia, two blue rubber blebs, two Meckelā€™s diverticula, one anastomotic ulcer, one reduplication); suspected Crohnā€™s disease: nā€Š=ā€Š20 (11 had Crohnā€™s disease); abdominal pain: nā€Š=ā€Š12 (six positive findings: three Crohnā€™s disease, two lymphonodular hyperplasia, one blue rubber bleb); protein loss: nā€Š=ā€Š9 (four lymphangectasia); malabsorption: nā€Š=ā€Š12 (seven positive findings: six enteropathy, one ascaris). No abnormalities overall: 45%. Conclusion: WCE is feasible and safe down to the age of 1.5 years. 20 children >4 years swallowed the capsule. The Advance introducer proved superior for endoscopic placement. The pathologies encountered showed age specificity and, unlike in adolescents, obscure gastrointestinal bleeding was the commonest indication

    Nokia on the slope: the failure of a hybrid open/closed source model

    Get PDF
    This case study explores the origins of Nokiaā€™s decline in the mobile technology market, as an unsuccessful attempt to introduce an open-source strategy into the business. Nokia created a hybrid model, which codified conflicting principles taken from closed and open mode of collaboration. A series of implementation problems resulted in Nokia struggling to attract open-source partners, growing issues with managing in-house staff and ultimately failing to develop a new mobile operating system fast enough to stay competitive

    Self-Rated Mental Stress and Exercise Training Response in Healthy Subjects

    Get PDF
    Purpose: Individual responses to aerobic training vary from almost none to a 40% increase in aerobic fitness in healthy subjects. We hypothesized that the baseline self-rated mental stress may influence to the training response. Methods: The study population included 44 healthy sedentary subjects (22 women) and 14 controls. The laboratory controlled training period was 2ā€‰weeks, including five sessions a week at an intensity of 75% of the maximum heart rate for 40ā€‰min/session. Self-rated mental stress was assessed by inquiry prior to the training period from 1 (low psychological resources and a lot of stressors in my life) to 10 (high psychological resources and no stressors in my life), respectively. Results: Mean peak oxygen uptake (VO2peak) increased from 34ā€‰Ā±ā€‰7 to 37ā€‰Ā±ā€‰7ā€‰mlā€‰kgāˆ’1ā€‰mināˆ’1 in training group (pā€‰<ā€‰0.001) and did not change in control group (from 34ā€‰Ā±ā€‰7 to 34ā€‰Ā±ā€‰7ā€‰mlā€‰kgāˆ’1ā€‰mināˆ’1). Among the training group, the self-rated stress at the baseline condition correlated with the change in fitness after training intervention, e.g., with the change in maximal power (rā€‰=ā€‰0.45, pā€‰=ā€‰0.002, W/kg) and with the change in VO2peak (rā€‰=ā€‰0.32, pā€‰=ā€‰0.039, mlā€‰kgāˆ’1ā€‰mināˆ’1). The self-rated stress at the baseline correlated with the change in fitness in both female and male, e.g., rā€‰=ā€‰0.44, pā€‰=ā€‰0.039 and rā€‰=ā€‰0.43, pā€‰=ā€‰0.045 for Ī”W/kg in female and male, respectively. Conclusion: As a novel finding the baseline self-rated mental stress is associated with the individual training response among healthy females and males after highly controlled aerobic training intervention. The changes in fitness were very low or absent in the subjects who experience their psychological resources low and a lot of stressors in their life at the beginning of aerobic training intervention

    Pim kinases are upregulated during Epstein-Barr virus infection and enhance EBNA2 activity

    Get PDF
    Latent Epstein-Barr virus (EBV) infection is strongly associated with B-cell proliferative diseases such as Burkitt's lymphoma. Here we show that the oncogenic serine/threonine kinases Pim-1 and Pim-2 enhance the activity of the viral transcriptional activator EBNA2. During EBV infection of primary B-lymphocytes, the mRNA expression levels of pint genes, especially of pim-2, are upregulated and remain elevated in latently infected B-cell lines. Thus, EBV-induced upregulation of Pim kinases and Pim-stimulated EBNA2 transcriptional activity may contribute to the ability of EBV to immortalize B-cells and predispose them to malignant growth. (C) 2005 Elsevier Inc. All rights reserved

    Solving ill-posed bilevel programs

    No full text
    This paper deals with ill-posed bilevel programs, i.e., problems admitting multiple lower-level solutions for some upper-level parameters. Many publications have been devoted to the standard optimistic case of this problem, where the difficulty is essentially moved from the objective function to the feasible set. This new problem is simpler but there is no guaranty to obtain local optimal solutions for the original optimistic problem by this process. Considering the intrinsic non-convexity of bilevel programs, computing local optimal solutions is the best one can hope to get in most cases. To achieve this goal, we start by establishing an equivalence between the original optimistic problem an a certain set-valued optimization problem. Next, we develop optimality conditions for the latter problem and show that they generalize all the results currently known in the literature on optimistic bilevel optimization. Our approach is then extended to multiobjective bilevel optimization, and completely new results are derived for problems with vector-valued upper- and lower-level objective functions. Numerical implementations of the results of this paper are provided on some examples, in order to demonstrate how the original optimistic problem can be solved in practice, by means of a special set-valued optimization problem

    The interlayer cohesive energy of graphite from thermal desorption of polyaromatic hydrocarbons

    Full text link
    We have studied the interaction of polyaromatic hydrocarbons (PAHs) with the basal plane of graphite using thermal desorption spectroscopy. Desorption kinetics of benzene, naphthalene, coronene and ovalene at sub-monolayer coverages yield activation energies of 0.50 eV, 0.85 eV, 1.40 eV and 2.1 eV, respectively. Benzene and naphthalene follow simple first order desorption kinetics while coronene and ovalene exhibit fractional order kinetics owing to the stability of 2-D adsorbate islands up to the desorption temperature. Pre-exponential frequency factors are found to be in the range 101410^{14}-1021sāˆ’110^{21} s^{-1} as obtained from both Falconer--Madix (isothermal desorption) analysis and Antoine's fit to vapour pressure data. The resulting binding energy per carbon atom of the PAH is 52Ā±52\pm5 meV and can be identified with the interlayer cohesive energy of graphite. The resulting cleavage energy of graphite is 61Ā±561\pm5~meV/atom which is considerably larger than previously reported experimental values.Comment: 8 pages, 4 figures, 2 table

    Spacelike Singularities and Hidden Symmetries of Gravity

    Get PDF
    We review the intimate connection between (super-)gravity close to a spacelike singularity (the "BKL-limit") and the theory of Lorentzian Kac-Moody algebras. We show that in this limit the gravitational theory can be reformulated in terms of billiard motion in a region of hyperbolic space, revealing that the dynamics is completely determined by a (possibly infinite) sequence of reflections, which are elements of a Lorentzian Coxeter group. Such Coxeter groups are the Weyl groups of infinite-dimensional Kac-Moody algebras, suggesting that these algebras yield symmetries of gravitational theories. Our presentation is aimed to be a self-contained and comprehensive treatment of the subject, with all the relevant mathematical background material introduced and explained in detail. We also review attempts at making the infinite-dimensional symmetries manifest, through the construction of a geodesic sigma model based on a Lorentzian Kac-Moody algebra. An explicit example is provided for the case of the hyperbolic algebra E10, which is conjectured to be an underlying symmetry of M-theory. Illustrations of this conjecture are also discussed in the context of cosmological solutions to eleven-dimensional supergravity.Comment: 228 pages. Typos corrected. References added. Subject index added. Published versio

    Localization of sucrose synthase in developing seed and siliques of Arabidopsis thaliana reveals diverse roles for SUS during development

    Get PDF
    This study investigated the roles of sucrose synthase (SUS) in developing seeds and siliques of Arabidopsis thaliana. Enzyme activity assays showed that SUS activity was highest in developing whole siliques and young rosette leaves compared with other tissues including mature leaves, stems, and flowers. Surprisingly, quantitative PCR analyses revealed little correlation between SUS activity and transcript expression, which indicated the importance of examining the role of SUS at the protein level. Therefore, immunolocalization was performed over a developmental time course to determine the previously unreported cellular localization of SUS in Arabidopsis seed and silique tissues. At 3ā€‰d and 10ā€‰d after flowering (daf), SUS protein localized to the silique wall, seed coat, funiculus, and endosperm. By 13 daf, SUS protein was detected in the embryo and aleurone layer, but was absent from the seed coat and funiculus. Starch grains were also present in the seed coat at 3 and 10 daf, but were absent at 13 daf. Co-localization of SUS protein and starch grains in the seed coat at 3 and 10 daf indicates that SUS may be involved in temporary starch deposition during the early stages of seed development, whilst in the later stages SUS metabolizes sucrose in the embryo and cotyledon. Within the silique wall, SUS localized specifically to the companion cells, indicating that SUS activity may be required to provide energy for phloem transport activities in the silique wall. The results highlight the diverse roles that SUS may play during the development of silique and seed in Arabidopsis

    QTL for phytosterol and sinapate ester content in Brassica napus L. collocate with the two erucic acid genes

    Get PDF
    Improving oil and protein quality for food and feed purposes is an important goal in rapeseed (Brassica napus L.) breeding programs. Rapeseed contains phytosterols, used to enrich food products, and sinapate esters, which are limiting the utilization of rapeseed proteins in the feed industry. Increasing the phytosterol content of oil and lowering sinapate ester content of meal could increase the value of the oilseed rape crop. The objective of the present study was to identify quantitative trait loci (QTL) for phytosterol and sinapate ester content in a winter rapeseed population of 148 doubled haploid lines, previously found to have a large variation for these two traits. This population also segregated for the two erucic acid genes. A close negative correlation was found between erucic acid and phytosterol content (Spearmanā€™s rank correlation, rsĀ =Ā āˆ’0.80**). For total phytosterol content, three QTL were detected, explaining 60% of the genetic variance. The two QTL with the strongest additive effects were mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. For sinapate ester content four QTL were detected, explaining 53% of the genetic variance. Again, a close negative correlation was found between erucic acid and sinapate ester content (rsĀ =Ā āˆ’0.66**) and the QTL with the strongest additive effects mapped on linkage groups N8 and N13 within the confidence intervals of the two erucic acid genes. The results suggests, that there is a pleiotropic effect of the two erucic acid genes on phytosterol and sinapate ester content; the effect of the alleles for low erucic acid content is to increase phytosterol and sinapate ester content. Possible reasons for this are discussed based on known biosynthetic pathways
    • ā€¦
    corecore