1,463 research outputs found

    Excess wing in glass-forming glycerol and LiCl-glycerol mixtures detected by neutron scattering

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    The relaxational dynamics in glass-forming glycerol and glycerol mixed with LiCl is in-vestigated using different neutron scattering techniques. The performed neutron spin-echo experiments, which extend up to relatively long relaxation-time scales of the order of 10 ns, should allow for the detection of contributions from the so-called excess wing. This phenomenon, whose microscopic origin is controversially discussed, arises in a variety of glass formers and, until now, was almost exclusively investigated by dielectric spectros-copy and light scattering. Here we show that the relaxational process causing the excess wing also can be detected by neutron scattering, which directly couples to density fluctua-tions.Comment: 8 pages, 6 figure

    Modeling and Reasoning over Distributed Systems using Aspect-Oriented Graph Grammars

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    Aspect-orientation is a relatively new paradigm that introduces abstractions to modularize the implementation of system-wide policies. It is based on a composition operation, called aspect weaving, that implicitly modifies a base system by performing related changes within the system modules. Aspect-oriented graph grammars (AOGG) extend the classic graph grammar formalism by defining aspects as sets of rule-based modifications over a base graph grammar. Despite the advantages of aspect-oriented concepts regarding modularity, the implicit nature of the aspect weaving operation may also introduce issues when reasoning about the system behavior. Since in AOGGs aspect weaving is characterized by means of rule-based rewriting, we can overcome these problems by using known analysis techniques from the graph transformation literature to study aspect composition. In this paper, we present a case study of a distributed client-server system with global policies, modeled as an aspect-oriented graph grammar, and discuss how to use the AGG tool to identify potential conflicts in aspect weaving

    Course of Stress during the Neonatal Intensive Care Unit Stay in Preterm Infants

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    Introduction: Understanding the course of stress during the neonatal intensive care unit stay may provide targets for interventions. Our aim was to describe the course of stress in preterm infants during the first 28 days of life, the influence of gestational age, and associations with clinical characteristics. Methods: In a single centre prospective cohort study, we included infants with a gestational age <30 weeks and/or birth weight <1,000 g. We measured stress over the first 28 days using the Neonatal Infant Stressor Scale (NISS). We plotted daily NISS total and subcategory scores by gestational age. The subcategories were (1) nursing, (2) skin-breaking, (3) monitoring and imaging, and (4) medical morbidity-related scores. We assessed associations of cumulative NISS scores over the first 7, 14, and 28 days with clinical characteristics using regression analyses. Results: We included 45 infants, with a median gestational age of 27 weeks. The mean daily NISS score was 66.5 (SD 8.7), with highest scores in the first 7 days of life. Scores decreased the slowest for the lowest gestational ages, in particular for nursing scores, rather than skin-breaking, monitoring and imaging, and medical morbidity-related scores. Adjusted for gestational age, infants with lower Apgar scores, sepsis, intraventricular haemorrhages, and on mechanical ventilation had significantly higher cumulative NISS scores at 7, 14, and 28 days. Conclusion: NISS scores varied greatly within infants and over time, with the highest mean scores in the first week after birth. The course of declining NISS scores in the first 28 days depended on gestational age at birth

    Maternal Anxiety, Infant Stress, and the Role of Live-Performed Music Therapy during NICU Stay in The Netherlands

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    Having an infant in the neonatal intensive care unit (NICU) elicits maternal anxiety, which may hamper parent−child bonding. We performed a prospective cohort study to describe anxiety in mothers of infants born before 30 weeks of gestation during NICU stay in The Netherlands, and investigated the influence of infant stress and gestational age. Second, we performed a randomized-controlled live-performed music therapy trial (LPMT trial) to investigate whether music therapy applied to the infant alleviated maternal anxiety. The relation between infant stress, gestational age, and maternal anxiety was measured in 45 mother−infant dyads, using the Neonatal Infant Stressor Scale and the State-Trait Anxiety Inventory (STAI). The effect of LPMT on anxiety was assessed in 21 mothers whose infants were assigned to either LPMT (n = 12) or waitlist (n = 9). Mothers completed the STAI before and after this period. Maternal anxiety decreased over time in all mothers, and was strongly related with infant stress (r = 0.706, p < 0.001), but not with gestational age. Anxiety scores decreased by 12% after LMPT, and increased by 1% after a waitlist period (p = 0.30). Our results indicate that LPMT in the weeks after birth may accelerate the reduction of maternal anxiety. Further research should focus on the effects on mother−child bonding

    Arterial inflammation in mice lacking the interleukin 1 receptor antagonist gene

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    Branch points and flexures in the high pressure arterial system have long been recognized as sites of unusually high turbulence and consequent stress in humans are foci for atherosclerotic lesions. We show that mice that are homozygous for a null mutation in the gene encoding an endogenous antiinflammatory cytokine, interleukin 1 receptor antagonist (IL-1ra), develop lethal arterial inflammation involving branch points and flexures of the aorta and its primary and secondary branches. We observe massive transmural infiltration of neutrophils, macrophages, and CD4(+) T cells. Animals appear to die from vessel wall collapse, stenosis, and organ infarction or from hemorrhage from ruptured aneurysms. Heterozygotes do not die from arteritis within a year of birth but do develop small lesions, which suggests that a reduced level of IL-1ra is insufficient to fully control inflammation in arteries. Our results demonstrate a surprisingly specific role for IL-1ra in the control of spontaneous inflammation in constitutively stressed artery walls, suggesting that expression of IL-1 is likely to have a significant role in signaling artery wall damage

    Porphyrin a as a precursor of heme a in Candida utilis

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    Background: An increased risk of major congenital abnormalities after IVF and ICSI has been described, but underlying mechanisms are unclear. This study evaluates the effects of ovarian hyperstimulation, the in vitro procedure and time to pregnancy (TTP) - as proxy for the severity of subfertility - on the prevalence of dysmorphic features. Design/methods: Participants were singletons born following controlled ovarian hyperstimulation-IVF/ICSI (COH-IVF/ICSI; n = 66), or modified natural cycle-IVF/ICSI (MNC-IVF/ICSI; n = 56), or to subfertile couples who conceived naturally (Sub-NC; n = 86). Dysmorphic features were assessed according to the method of Merks et al., and are classified into 'minor variants' (minor anomalies or common variants) and 'abnormalities' (clinically relevant or irrelevant abnormalities). We focussed on minor anomalies as they indicate altered embryonic development and because they have the advantage of a higher prevalence. Results: The prevalences of any of the outcome measures were similar in the three groups. One or more minor anomalies, our primary outcome measure, occurred in 50% of COH-IVFACSI, 54% of MNC-IVF/ICSI and 53% of Sub-NC children. TTP in years was significantly associated with abnormalities (adjusted0R= 120; 95%CI = 1.02-1.40). especially with clinically relevant abnormalities (adjustedOR = 1.22; 95%CI = 1.01-1.48). Conclusions: The study indicates that ovarian hyperstimulation and the in vitro procedure are not associated with an increase in dysmorphic features. The positive association between TTP and clinically relevant abnormalities suggests a role of the underlying subfertility and its determinants in the genesis of dysmorphic features. (C) 2012 Published by Elsevier Ireland Lt

    Developing a policy for paediatric biobanks: Principles for good practice

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    The participation of minors in biobank research can offer great benefits for science and health care. However, as minors are a vulnerable population they are also in need of adequate protective measures when they are enrolled in research. Research using biobanked biological samples from children poses additional ethical issues to those raised by research using adult biobanks. For example, small children have only limited capacity, if any, to understand the meaning and implications of the research and to give a documented agreement to it. Older minors are gradually acquiring this capacity. We describe principles for good practice related to the inclusion of minors in biobank research, focusing on issues related to benefits and subsidiarity, consent, proportionality and return of results. Some of these issues are currently heavily debated, and we conclude by providing principles for good practice for policy makers of biobanks, researchers and anyone involved in dealing with stored tissue samples from children. Actual implementation of the principles will vary according to different jurisdictions
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