2,285 research outputs found

    Eigenvalue Decomposition as a Generalized Synchronization Cluster Analysis

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    Motivated by the recent demonstration of its use as a tool for the detection and characterization of phase-shape correlations in multivariate time series, we show that eigenvalue decomposition can also be applied to a matrix of indices of bivariate phase synchronization strength. The resulting method is able to identify clusters of synchronized oscillators, and to quantify their strength as well as the degree of involvement of an oscillator in a cluster. Since for the case of a single cluster the method gives similar results as our previous approach, it can be seen as a generalized Synchronization Cluster Analysis, extending its field of application to more complex situations. The performance of the method is tested by applying it to simulation data.Comment: Submitted Oct 2005, accepted Jan 2006, "published" Oct 2007, actually available Jan 200

    Failure to confirm influence of Methyltetrahydrofolate reductase (MTHFR) polymorphisms on age at onset of Huntington disease

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    BACKGROUND: Huntington disease (HD) is a fully penetrant, autosomal dominantly inherited disorder associated with abnormal expansions of a stretch of perfect CAG repeats in the 5' part of the IT15 gene. The number of repeat units is highly predictive for the age at onset (AO) of the disorder. But AO is only modestly correlated with repeat length when intermediate HD expansions are considered. Recently, suggestive association has been reported between a single nucleotide polymorphism (SNP; rs1801131, also known as A1298C) in the methyltetrahydrofolate reductase (MTHFR) gene and AO of HD. 5,10-MTHFR is a key enzyme in the folate metabolism, diverting metabolites toward methylation reactions or nucleotide synthesis. Using part of a previously established study cohort plus additional patients and appropriate statistical methods, we reinvestigated two polymorphisms in the MTHFR gene, C677T and A1298C, as well as their association with AO in 167 HD patients. RESULTS: There was no statistically significant impact on AO for HD patients, neither of MTHFR SNPs nor of the combinations thereof. CONCLUSION: Contrary to previously described evidence the A1298C polymorphism in the MTHFR gene does not appear to modulate AO of HD patients

    The Diversity of Aphidlion-like Larvae over the Last 130 Million Years

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    Aphidlions are larvae of certain lacewings (Neuroptera), and more precisely larvae of the groups Chrysopidae, green lacewings, and Hemerobiidae, brown lacewings. The name ‘aphidlion’ originates from their ecological function as specialised predators of aphids. Accordingly, they also play an economic role as biological pest control. Aphidlions have, mostly, elongated spindle-shaped bodies, and similarly to most lacewing larvae they are equipped with a pair of venom-injecting stylets. Fossils interpreted as aphidlions are known to be preserved in amber from the Cretaceous (130 and 100 million years ago), the Eocene (about 35 million years ago) and the Miocene (about 15 million years ago) ages. In this study, new aphidlion-like larvae are reported from Cretaceous amber from Myanmar (about 100 million years old) and Eocene Baltic amber. The shapes of head and stylets were compared between the different time slices. With the newly described fossils and specimens from the literature, a total of 361 specimens could be included in the analysis: 70 specimens from the Cretaceous, 5 from the Eocene, 3 from the Miocene, 188 extant larvae of Chrysopidae, and 95 extant larvae of Hemerobiidae. The results indicate that the diversity of head shapes remains largely unchanged over time, yet there is a certain increase in the diversity of head shapes in the larvae of Hemerobiidae. In certain other groups of Neuroptera, a distinct decrease in the diversity of head shapes in larval stages was observed

    Workflow to improve patient recruitment for clinical trials within hospital information systems – a case-study

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    <p>Abstract</p> <p>Background</p> <p>The identification of suitable patients is a common problem in clinical trials that is especially evident in tertiary care hospitals.</p> <p>Methods</p> <p>We developed and analysed a workflow, which uses routine data captured during patient care in a hospital information system (HIS), to identify potential trial subjects. Study nurses or physicians are notified automatically by email and verify eligibility.</p> <p>Results</p> <p>As a case study we implemented the system for acute myeloid leukemia (AML) trials in Münster. During a test period of 50 days 41 patients were identified by the system. 13 could be included as new trial patients, 7 were already included during earlier visits. According to review of paper records no AML trial patient was missed by the system. In addition, the hospital information system further allowed to preselect patients for specific trials based on their disease status and individual characteristics.</p> <p>Conclusion</p> <p>Routine HIS data can be used to support patient recruitment for clinical trials by means of an automated notification workflow.</p

    Volatile organic compounds as disease predictors in newborn infants: a systematic review

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    Volatile organic compounds (VOCs) detected in human breath, urine, stool, sweat, saliva, and blood result from metabolic processes in the body during health or disease. Using sophisticated measurement systems, small amounts of these compounds can be detected in the above bodily fluids. Multiple studies in adults and children have shown the potential of these compounds to differentiate between healthy individuals and patients by detecting profiles of compounds in non-invasively collected samples. However, the detection of biomarkers in VOCs from neonates is particularly attractive due to the non-invasive nature of its approach, and its ability to track disease progress by longitudinal sampling. In this work we have reviewed the literature on the use of VOCs in neonates and identified areas for future work. Overview of VOCs and their usefulness as metabolic signatures. Detailed review of studies on VOCs in neonates Learn about potential uses of VOCs as derived from adult and paediatric studies. Examine current limitations and identify future work. Detailed studies on VOCs involving neonatal patients including sick preterm infants and term infants with specific morbidities are needed. These studies should collect longitudinal samples using non-invasive methods for the detection of potential biomarkers. Underlying metabolic processes need to be identified so that any therapeutic options can be clarified

    From field to plate: How do bacterial enteric pathogens interact with ready-to-eat fruit and vegetables, causing disease outbreaks?

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    Ready-to-eat fruit and vegetables are a convenient source of nutrients and fibre for consumers, and are generally safe to eat, but are vulnerable to contamination with human enteric bacterial pathogens. Over the last decade, Salmonella spp., pathogenic Escherichia coli, and Listeria monocytogenes have been linked to most of the bacterial outbreaks of foodborne illness associated with fresh produce. The origins of these outbreaks have been traced to multiple sources of contamination from pre-harvest (soil, seeds, irrigation water, domestic and wild animal faecal matter) or post-harvest operations (storage, preparation and packaging). These pathogens have developed multiple processes for successful attachment, survival and colonization conferring them the ability to adapt to multiple environments. However, these processes differ across bacterial strains from the same species, and across different plant species or cultivars. In a competitive environment, additional risk factors are the plant microbiome phyllosphere and the plant responses; both factors directly modulate the survival of the pathogens on the leaf's surface. Understanding the mechanisms involved in bacterial attachment to, colonization of, and proliferation, on fresh produce and the role of the plant in resisting bacterial contamination is therefore crucial to reducing future outbreaks

    Growth independent rhamnolipid production from glucose using the non-pathogenic Pseudomonas putida KT2440

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    <p>Abstract</p> <p>Background</p> <p>Rhamnolipids are potent biosurfactants with high potential for industrial applications. However, rhamnolipids are currently produced with the opportunistic pathogen <it>Pseudomonas aeruginosa </it>during growth on hydrophobic substrates such as plant oils. The heterologous production of rhamnolipids entails two essential advantages: Disconnecting the rhamnolipid biosynthesis from the complex quorum sensing regulation and the opportunity of avoiding pathogenic production strains, in particular <it>P. aeruginosa</it>. In addition, separation of rhamnolipids from fatty acids is difficult and hence costly.</p> <p>Results</p> <p>Here, the metabolic engineering of a rhamnolipid producing <it>Pseudomonas putida </it>KT2440, a strain certified as safety strain using glucose as carbon source to avoid cumbersome product purification, is reported. Notably, <it>P. putida </it>KT2440 features almost no changes in growth rate and lag-phase in the presence of high concentrations of rhamnolipids (> 90 g/L) in contrast to the industrially important bacteria <it>Bacillus subtilis, Corynebacterium glutamicum</it>, and <it>Escherichia coli. P. putida </it>KT2440 expressing the <it>rhlAB</it>-genes from <it>P. aeruginosa </it>PAO1 produces mono-rhamnolipids of <it>P. aeruginosa </it>PAO1 type (mainly C<sub>10</sub>:C<sub>10</sub>). The metabolic network was optimized in silico for rhamnolipid synthesis from glucose. In addition, a first genetic optimization, the removal of polyhydroxyalkanoate formation as competing pathway, was implemented. The final strain had production rates in the range of <it>P. aeruginosa </it>PAO1 at yields of about 0.15 g/g<sub>glucose </sub>corresponding to 32% of the theoretical optimum. What's more, rhamnolipid production was independent from biomass formation, a trait that can be exploited for high rhamnolipid production without high biomass formation.</p> <p>Conclusions</p> <p>A functional alternative to the pathogenic rhamnolipid producer <it>P. aeruginosa </it>was constructed and characterized. <it>P. putida </it>KT24C1 pVLT31_<it>rhlAB </it>featured the highest yield and titer reported from heterologous rhamnolipid producers with glucose as carbon source. Notably, rhamnolipid production was uncoupled from biomass formation, which allows optimal distribution of resources towards rhamnolipid synthesis. The results are discussed in the context of rational strain engineering by using the concepts of synthetic biology like chassis cells and orthogonality, thereby avoiding the complex regulatory programs of rhamnolipid production existing in the natural producer <it>P. aeruginosa</it>.</p

    Evaluating potential olive orchard sugar food sources for the olive fly parasitoid Psyttalia concolor

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    Olive fruit fly Bactrocera oleae (Rossi) (Diptera: Tephritidae) is a major olive pest in the Mediterranean basin where increasing insecticide resistance has enhanced damage and necessitates more reliance on other control strategies, such as biological control. Provision of floral resources has been reported to improve the effectiveness of natural enemies. Here, we tested the effect of six plant nectars and two honeydew sources on the survival of Psyttalia concolor (Szépligeti) (Hymenoptera: Braconidae), a parasitoid wasp used in the biological control of olive fruit fly. Our results showed a positive effect on survival associated with nectars of Anchusa azurea Mill., Rosmarinus officinalis L., Lavatera cretica L. and Calamintha nepeta (L.) Savi, while honeydew proved to be a valuable alternative food source. When offering flowers directly to insects, Anchusa azurea, Lavatera cretica, and Foeniculum vulgare L. were found to be the most beneficial species, indicating also that P. concolor feeds predominantly on shallow corollas

    A Phase I Dose Escalation Study of the Triple Angiokinase Inhibitor Nintedanib Combined with Low-Dose Cytarabine in Elderly Patients with Acute Myeloid Leukemia

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    Nintedanib (BIBF 1120), a potent multikinase inhibitor of VEGFR-1/-2/-3, FGFR-1/-2/-3 and PDGFR-α/-β, exerts growth inhibitory and pro-apoptotic effects in myeloid leukemic cells, especially when used in combination with cytarabine. This phase I study evaluated nintedanib in combination with low-dose cytarabine (LDAC) in elderly patients with untreated or relapsed/refractory acute myeloid leukemia (AML) ineligible for intensive chemotherapy in a 3+3 design. Nintedanib (dose levels 100, 150, and 200 mg orally twice daily) and LDAC (20 mg subcutaneous injection twice daily for 10 days) were administered in 28-day cycles. Dose-limiting toxicity (DLT) was defined as non-hematological severe adverse reaction CTC grade ≥ 4 with possible or definite relationship to nintedanib. Between April 2012 and October 2013, 13 patients (median age 73 [range: 62–86] years) were enrolled. One patient did not receive study medication and was replaced. Nine (69%) patients had relapsed or refractory disease and 6 (46%) patients had unfavorable cytogenetics. The most frequently reported treatment-related adverse events (AE) were gastrointestinal events. Twelve SAEs irrespective of relatedness were reported. Two SUSARs were observed, one fatal hypercalcemia and one fatal gastrointestinal infection. Two patients (17%) with relapsed AML achieved a complete remission (one CR, one CRi) and bone marrow blast reductions without fulfilling PR criteria were observed in 3 patients (25%). One-year overall survival was 33%. Nintedanib combined with LDAC shows an adequate safety profile and survival data are promising in a difficult-to-treat patient population. Continuation of this trial with a phase II recommended dose of 2 x 200 mg nintedanib in a randomized, placebo-controlled phase II study is planned. The trial is registered to EudraCT as 2011-001086-41

    Classical Fields Near Thermal Equilibrium

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    We discuss the classical limit for the long-distance (``soft'') modes of a quantum field when the hard modes of the field are in thermal equilibrium. We address the question of the correct semiclassical dynamics when a momentum cut-off is introduced. Higher order contributions leads to a stochastic interpretation for the effective action in analogy to Quantum Brownian Motion, resulting in dissipation and decoherence for the evolution of the soft modes. Particular emphasis is put on the understanding of dissipation. Our discussion focuses mostly on scalar fields, but we make some remarks on the extension to gauge theories.Comment: REVTeX, 6 figure
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